diff --git a/src/Umbraco.Core/Persistence/IQueryRepository.cs b/src/Umbraco.Core/Persistence/IQueryRepository.cs
index 6623fbf0fc..1a8dbaf971 100644
--- a/src/Umbraco.Core/Persistence/IQueryRepository.cs
+++ b/src/Umbraco.Core/Persistence/IQueryRepository.cs
@@ -1,4 +1,4 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 using Umbraco.Cms.Core.Persistence.Querying;
 
 namespace Umbraco.Cms.Core.Persistence
@@ -11,7 +11,7 @@ namespace Umbraco.Cms.Core.Persistence
         /// <summary>
         /// Gets entities.
         /// </summary>
-        IEnumerable<TEntity>? Get(IQuery<TEntity> query);
+        IEnumerable<TEntity> Get(IQuery<TEntity> query);
 
         /// <summary>
         /// Counts entities.
diff --git a/src/Umbraco.Core/Services/AuditService.cs b/src/Umbraco.Core/Services/AuditService.cs
index e9a35f80ba..f7560afa93 100644
--- a/src/Umbraco.Core/Services/AuditService.cs
+++ b/src/Umbraco.Core/Services/AuditService.cs
@@ -34,7 +34,7 @@ namespace Umbraco.Cms.Core.Services.Implement
             }
         }
 
-        public IEnumerable<IAuditItem>? GetLogs(int objectId)
+        public IEnumerable<IAuditItem> GetLogs(int objectId)
         {
             using (var scope = ScopeProvider.CreateCoreScope())
             {
diff --git a/src/Umbraco.Core/Services/ConsentService.cs b/src/Umbraco.Core/Services/ConsentService.cs
index 9a767d9c4e..d37e2e4d0f 100644
--- a/src/Umbraco.Core/Services/ConsentService.cs
+++ b/src/Umbraco.Core/Services/ConsentService.cs
@@ -57,7 +57,7 @@ namespace Umbraco.Cms.Core.Services
         }
 
         /// <inheritdoc />
-        public IEnumerable<IConsent>? LookupConsent(string? source = null, string? context = null, string? action = null,
+        public IEnumerable<IConsent> LookupConsent(string? source = null, string? context = null, string? action = null,
             bool sourceStartsWith = false, bool contextStartsWith = false, bool actionStartsWith = false,
             bool includeHistory = false)
         {
diff --git a/src/Umbraco.Core/Services/ContentService.cs b/src/Umbraco.Core/Services/ContentService.cs
index e365020ab4..a2fa13a346 100644
--- a/src/Umbraco.Core/Services/ContentService.cs
+++ b/src/Umbraco.Core/Services/ContentService.cs
@@ -513,7 +513,7 @@ namespace Umbraco.Cms.Core.Services
         /// <returns>
         ///     <see cref="IContent" />
         /// </returns>
-        public IEnumerable<IContent>? GetByIds(IEnumerable<Guid> ids)
+        public IEnumerable<IContent> GetByIds(IEnumerable<Guid> ids)
         {
             Guid[] idsA = ids.ToArray();
             if (idsA.Length == 0)
@@ -533,7 +533,7 @@ namespace Umbraco.Cms.Core.Services
                     return idsA.Select(x => index.TryGetValue(x, out IContent? c) ? c : null).WhereNotNull();
                 }
 
-                return null;
+                return Enumerable.Empty<IContent>();
             }
         }
 
@@ -600,7 +600,7 @@ namespace Umbraco.Cms.Core.Services
         /// <param name="level">The level to retrieve Content from</param>
         /// <returns>An Enumerable list of <see cref="IContent" /> objects</returns>
         /// <remarks>Contrary to most methods, this method filters out trashed content items.</remarks>
-        public IEnumerable<IContent>? GetByLevel(int level)
+        public IEnumerable<IContent> GetByLevel(int level)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -670,10 +670,15 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="id">Id of the <see cref="IContent" /> to retrieve ancestors for</param>
         /// <returns>An Enumerable list of <see cref="IContent" /> objects</returns>
-        public IEnumerable<IContent>? GetAncestors(int id)
+        public IEnumerable<IContent> GetAncestors(int id)
         {
             // intentionally not locking
             IContent? content = GetById(id);
+            if (content is null)
+            {
+                return Enumerable.Empty<IContent>();
+            }
+
             return GetAncestors(content);
         }
 
@@ -682,10 +687,10 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="content"><see cref="IContent" /> to retrieve ancestors for</param>
         /// <returns>An Enumerable list of <see cref="IContent" /> objects</returns>
-        public IEnumerable<IContent>? GetAncestors(IContent? content)
+        public IEnumerable<IContent> GetAncestors(IContent content)
         {
             //null check otherwise we get exceptions
-            if (content?.Path.IsNullOrWhiteSpace() ?? true)
+            if (content.Path.IsNullOrWhiteSpace())
             {
                 return Enumerable.Empty<IContent>();
             }
@@ -708,13 +713,13 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="id">Id of the Parent to retrieve Children from</param>
         /// <returns>An Enumerable list of published <see cref="IContent" /> objects</returns>
-        public IEnumerable<IContent>? GetPublishedChildren(int id)
+        public IEnumerable<IContent> GetPublishedChildren(int id)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
                 scope.ReadLock(Constants.Locks.ContentTree);
                 IQuery<IContent>? query = Query<IContent>().Where(x => x.ParentId == id && x.Published);
-                return _documentRepository.Get(query)?.OrderBy(x => x.SortOrder);
+                return _documentRepository.Get(query).OrderBy(x => x.SortOrder);
             }
         }
 
@@ -849,7 +854,7 @@ namespace Umbraco.Cms.Core.Services
             {
                 scope.ReadLock(Constants.Locks.ContentTree);
                 IQuery<IContent> query = Query<IContent>().Where(x => x.ParentId == Constants.System.Root);
-                return _documentRepository.Get(query) ?? Enumerable.Empty<IContent>();
+                return _documentRepository.Get(query);
             }
         }
 
@@ -857,7 +862,7 @@ namespace Umbraco.Cms.Core.Services
         ///     Gets all published content items
         /// </summary>
         /// <returns></returns>
-        internal IEnumerable<IContent>? GetAllPublished()
+        internal IEnumerable<IContent> GetAllPublished()
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -2559,7 +2564,7 @@ namespace Umbraco.Cms.Core.Services
 
                 // emptying the recycle bin means deleting whatever is in there - do it properly!
                 IQuery<IContent>? query = Query<IContent>().Where(x => x.ParentId == Constants.System.RecycleBinContent);
-                IContent[]? contents = _documentRepository.Get(query)?.ToArray();
+                IContent[] contents = _documentRepository.Get(query).ToArray();
 
                 var emptyingRecycleBinNotification = new ContentEmptyingRecycleBinNotification(contents, eventMessages);
                 if (scope.Notifications.PublishCancelable(emptyingRecycleBinNotification))
@@ -2982,7 +2987,7 @@ namespace Umbraco.Cms.Core.Services
             var pathMatch = content.Path + ",";
             IQuery<IContent> query = Query<IContent>()
                 .Where(x => x.Id != content.Id && x.Path.StartsWith(pathMatch) /*&& x.Trashed == false*/);
-            IEnumerable<IContent>? contents = _documentRepository.Get(query);
+            IEnumerable<IContent> contents = _documentRepository.Get(query);
 
             // beware! contents contains all published version below content
             // including those that are not directly published because below an unpublished content
@@ -3355,7 +3360,7 @@ namespace Umbraco.Cms.Core.Services
                 scope.WriteLock(Constants.Locks.ContentTree);
 
                 IQuery<IContent> query = Query<IContent>().WhereIn(x => x.ContentTypeId, contentTypeIdsA);
-                IContent[]? contents = _documentRepository.Get(query)?.ToArray();
+                IContent[] contents = _documentRepository.Get(query).ToArray();
 
                 if (contents is null)
                 {
@@ -3383,15 +3388,12 @@ namespace Umbraco.Cms.Core.Services
                     // if current content has children, move them to trash
                     IContent c = content;
                     IQuery<IContent> childQuery = Query<IContent>().Where(x => x.ParentId == c.Id);
-                    IEnumerable<IContent>? children = _documentRepository.Get(childQuery);
-                    if (children is not null)
+                    IEnumerable<IContent> children = _documentRepository.Get(childQuery);
+                    foreach (IContent child in children)
                     {
-                        foreach (IContent child in children)
-                        {
-                            // see MoveToRecycleBin
-                            PerformMoveLocked(child, Constants.System.RecycleBinContent, null, userId, moves, true);
-                            changes.Add(new TreeChange<IContent>(content, TreeChangeTypes.RefreshBranch));
-                        }
+                        // see MoveToRecycleBin
+                        PerformMoveLocked(child, Constants.System.RecycleBinContent, null, userId, moves, true);
+                        changes.Add(new TreeChange<IContent>(content, TreeChangeTypes.RefreshBranch));
                     }
 
                     // delete content
@@ -3442,7 +3444,7 @@ namespace Umbraco.Cms.Core.Services
             scope.ReadLock(Constants.Locks.ContentTypes);
 
             IQuery<IContentType> query = Query<IContentType>().Where(x => x.Alias == contentTypeAlias);
-            IContentType? contentType = _contentTypeRepository.Get(query)?.FirstOrDefault();
+            IContentType? contentType = _contentTypeRepository.Get(query).FirstOrDefault();
 
             if (contentType == null)
             {
@@ -3604,7 +3606,7 @@ namespace Umbraco.Cms.Core.Services
             return content;
         }
 
-        public IEnumerable<IContent>? GetBlueprintsForContentTypes(params int[] contentTypeId)
+        public IEnumerable<IContent> GetBlueprintsForContentTypes(params int[] contentTypeId)
         {
             using (ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -3614,7 +3616,7 @@ namespace Umbraco.Cms.Core.Services
                     query.Where(x => contentTypeId.Contains(x.ContentTypeId));
                 }
 
-                return _documentBlueprintRepository.Get(query)?.Select(x =>
+                return _documentBlueprintRepository.Get(query).Select(x =>
                 {
                     x.Blueprint = true;
                     return x;
diff --git a/src/Umbraco.Core/Services/ContentTypeServiceBaseOfTRepositoryTItemTService.cs b/src/Umbraco.Core/Services/ContentTypeServiceBaseOfTRepositoryTItemTService.cs
index 7eb87b28a9..10775e2ce3 100644
--- a/src/Umbraco.Core/Services/ContentTypeServiceBaseOfTRepositoryTItemTService.cs
+++ b/src/Umbraco.Core/Services/ContentTypeServiceBaseOfTRepositoryTItemTService.cs
@@ -312,7 +312,7 @@ namespace Umbraco.Cms.Core.Services
             }
         }
 
-        public IEnumerable<TItem>? GetChildren(int id)
+        public IEnumerable<TItem> GetChildren(int id)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -322,7 +322,7 @@ namespace Umbraco.Cms.Core.Services
             }
         }
 
-        public IEnumerable<TItem>? GetChildren(Guid id)
+        public IEnumerable<TItem> GetChildren(Guid id)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -403,7 +403,7 @@ namespace Umbraco.Cms.Core.Services
                 {
                     var i = ids.Pop();
                     var query = Query<TItem>().Where(x => x.ParentId == i);
-                    var result = Repository.Get(query)?.ToArray();
+                    var result = Repository.Get(query).ToArray();
 
                     if (result is not null)
                     {
diff --git a/src/Umbraco.Core/Services/DataTypeService.cs b/src/Umbraco.Core/Services/DataTypeService.cs
index 007b8e8357..5c9d5847ed 100644
--- a/src/Umbraco.Core/Services/DataTypeService.cs
+++ b/src/Umbraco.Core/Services/DataTypeService.cs
@@ -164,7 +164,7 @@ namespace Umbraco.Cms.Core.Services.Implement
             }
         }
 
-        public IEnumerable<EntityContainer>? GetContainers(IDataType dataType)
+        public IEnumerable<EntityContainer> GetContainers(IDataType dataType)
         {
             var ancestorIds = dataType.Path.Split(Constants.CharArrays.Comma, StringSplitOptions.RemoveEmptyEntries)
                 .Select(x =>
@@ -178,7 +178,7 @@ namespace Umbraco.Cms.Core.Services.Implement
             return GetContainers(ancestorIds);
         }
 
-        public IEnumerable<EntityContainer>? GetContainers(int[] containerIds)
+        public IEnumerable<EntityContainer> GetContainers(int[] containerIds)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -333,7 +333,7 @@ namespace Umbraco.Cms.Core.Services.Implement
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
                 var query = Query<IDataType>().Where(x => x.Key == id);
-                var dataType = _dataTypeRepository.Get(query)?.FirstOrDefault();
+                var dataType = _dataTypeRepository.Get(query).FirstOrDefault();
                 ConvertMissingEditorOfDataTypeToLabel(dataType);
                 return dataType;
             }
@@ -344,16 +344,12 @@ namespace Umbraco.Cms.Core.Services.Implement
         /// </summary>
         /// <param name="propertyEditorAlias">Alias of the property editor</param>
         /// <returns>Collection of <see cref="IDataType"/> objects with a matching control id</returns>
-        public IEnumerable<IDataType>? GetByEditorAlias(string propertyEditorAlias)
+        public IEnumerable<IDataType> GetByEditorAlias(string propertyEditorAlias)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
                 var query = Query<IDataType>().Where(x => x.EditorAlias == propertyEditorAlias);
                 var dataType = _dataTypeRepository.Get(query);
-                if (dataType is null)
-                {
-                    return null;
-                }
                 ConvertMissingEditorsOfDataTypesToLabels(dataType);
                 return dataType;
             }
diff --git a/src/Umbraco.Core/Services/EntityXmlSerializer.cs b/src/Umbraco.Core/Services/EntityXmlSerializer.cs
index a5500ac690..8123dd06da 100644
--- a/src/Umbraco.Core/Services/EntityXmlSerializer.cs
+++ b/src/Umbraco.Core/Services/EntityXmlSerializer.cs
@@ -196,14 +196,11 @@ namespace Umbraco.Cms.Core.Services
             if (dataType.Level != 1)
             {
                 //get URL encoded folder names
-                var folders = _dataTypeService.GetContainers(dataType)?
+                IOrderedEnumerable<EntityContainer> folders = _dataTypeService.GetContainers(dataType)
                     .OrderBy(x => x.Level);
 
-                if (folders is not null)
-                {
-                    folderNames = string.Join("/", folders.Select(x => WebUtility.UrlEncode(x.Name)).ToArray());
-                    folderKeys = string.Join("/", folders.Select(x => x.Key).ToArray());
-                }
+                folderNames = string.Join("/", folders.Select(x => WebUtility.UrlEncode(x.Name)).ToArray());
+                folderKeys = string.Join("/", folders.Select(x => x.Key).ToArray());
             }
 
             if (string.IsNullOrWhiteSpace(folderNames) == false)
diff --git a/src/Umbraco.Core/Services/ExternalLoginService.cs b/src/Umbraco.Core/Services/ExternalLoginService.cs
index 4fde36ad37..d934e89528 100644
--- a/src/Umbraco.Core/Services/ExternalLoginService.cs
+++ b/src/Umbraco.Core/Services/ExternalLoginService.cs
@@ -33,12 +33,12 @@ namespace Umbraco.Cms.Core.Services
 
         /// <inheritdoc />
         [Obsolete("Use overload that takes a user/member key (Guid).")]
-        public IEnumerable<IIdentityUserLogin>? GetExternalLogins(int userId)
+        public IEnumerable<IIdentityUserLogin> GetExternalLogins(int userId)
             => GetExternalLogins(userId.ToGuid());
 
         /// <inheritdoc />
         [Obsolete("Use overload that takes a user/member key (Guid).")]
-        public IEnumerable<IIdentityUserToken>? GetExternalLoginTokens(int userId) =>
+        public IEnumerable<IIdentityUserToken> GetExternalLoginTokens(int userId) =>
             GetExternalLoginTokens(userId.ToGuid());
 
         /// <inheritdoc />
@@ -57,32 +57,32 @@ namespace Umbraco.Cms.Core.Services
             => DeleteUserLogins(userId.ToGuid());
 
         /// <inheritdoc />
-        public IEnumerable<IIdentityUserLogin>? GetExternalLogins(Guid userOrMemberKey)
+        public IEnumerable<IIdentityUserLogin> GetExternalLogins(Guid userOrMemberKey)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
-                return _externalLoginRepository.Get(Query<IIdentityUserLogin>().Where(x => x.Key == userOrMemberKey))?
+                return _externalLoginRepository.Get(Query<IIdentityUserLogin>().Where(x => x.Key == userOrMemberKey))
                     .ToList();
             }
         }
 
         /// <inheritdoc />
-        public IEnumerable<IIdentityUserToken>? GetExternalLoginTokens(Guid userOrMemberKey)
+        public IEnumerable<IIdentityUserToken> GetExternalLoginTokens(Guid userOrMemberKey)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
-                return _externalLoginRepository.Get(Query<IIdentityUserToken>().Where(x => x.Key == userOrMemberKey))?
+                return _externalLoginRepository.Get(Query<IIdentityUserToken>().Where(x => x.Key == userOrMemberKey))
                     .ToList();
             }
         }
 
         /// <inheritdoc />
-        public IEnumerable<IIdentityUserLogin>? Find(string loginProvider, string providerKey)
+        public IEnumerable<IIdentityUserLogin> Find(string loginProvider, string providerKey)
         {
             using (var scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
                 return _externalLoginRepository.Get(Query<IIdentityUserLogin>()
-                    .Where(x => x.ProviderKey == providerKey && x.LoginProvider == loginProvider))?
+                    .Where(x => x.ProviderKey == providerKey && x.LoginProvider == loginProvider))
                     .ToList();
             }
         }
diff --git a/src/Umbraco.Core/Services/FileService.cs b/src/Umbraco.Core/Services/FileService.cs
index 27ec6660e5..2d901ffacd 100644
--- a/src/Umbraco.Core/Services/FileService.cs
+++ b/src/Umbraco.Core/Services/FileService.cs
@@ -153,7 +153,7 @@ namespace Umbraco.Cms.Core.Services
         }
 
         /// <inheritdoc />
-        public Stream? GetStylesheetFileContentStream(string filepath)
+        public Stream GetStylesheetFileContentStream(string filepath)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -283,7 +283,7 @@ namespace Umbraco.Cms.Core.Services
         }
 
         /// <inheritdoc />
-        public Stream? GetScriptFileContentStream(string filepath)
+        public Stream GetScriptFileContentStream(string filepath)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -597,11 +597,7 @@ namespace Umbraco.Cms.Core.Services
                 fileName = $"{fileName}.cshtml";
             }
 
-            Stream? fs = _templateRepository.GetFileContentStream(fileName);
-            if (fs == null)
-            {
-                return null;
-            }
+            Stream fs = _templateRepository.GetFileContentStream(fileName);
 
             using (var view = new StreamReader(fs))
             {
@@ -610,7 +606,7 @@ namespace Umbraco.Cms.Core.Services
         }
 
         /// <inheritdoc />
-        public Stream? GetTemplateFileContentStream(string filepath)
+        public Stream GetTemplateFileContentStream(string filepath)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -898,7 +894,7 @@ namespace Umbraco.Cms.Core.Services
         }
 
         /// <inheritdoc />
-        public Stream? GetPartialViewFileContentStream(string filepath)
+        public Stream GetPartialViewFileContentStream(string filepath)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
@@ -926,7 +922,7 @@ namespace Umbraco.Cms.Core.Services
         }
 
         /// <inheritdoc />
-        public Stream? GetPartialViewMacroFileContentStream(string filepath)
+        public Stream GetPartialViewMacroFileContentStream(string filepath)
         {
             using (ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true))
             {
diff --git a/src/Umbraco.Core/Services/IAuditService.cs b/src/Umbraco.Core/Services/IAuditService.cs
index cbc3db8239..df816960a3 100644
--- a/src/Umbraco.Core/Services/IAuditService.cs
+++ b/src/Umbraco.Core/Services/IAuditService.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using Umbraco.Cms.Core.Models;
 using Umbraco.Cms.Core.Persistence.Querying;
@@ -12,7 +12,7 @@ namespace Umbraco.Cms.Core.Services
     {
         void Add(AuditType type, int userId, int objectId, string? entityType, string comment, string? parameters = null);
 
-        IEnumerable<IAuditItem>? GetLogs(int objectId);
+        IEnumerable<IAuditItem> GetLogs(int objectId);
         IEnumerable<IAuditItem> GetUserLogs(int userId, AuditType type, DateTime? sinceDate = null);
         IEnumerable<IAuditItem> GetLogs(AuditType type, DateTime? sinceDate = null);
         void CleanLogs(int maximumAgeOfLogsInMinutes);
diff --git a/src/Umbraco.Core/Services/IConsentService.cs b/src/Umbraco.Core/Services/IConsentService.cs
index 50222a7f28..d191caebe2 100644
--- a/src/Umbraco.Core/Services/IConsentService.cs
+++ b/src/Umbraco.Core/Services/IConsentService.cs
@@ -1,4 +1,4 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 using Umbraco.Cms.Core.Models;
 
 namespace Umbraco.Cms.Core.Services
@@ -38,7 +38,7 @@ namespace Umbraco.Cms.Core.Services
         /// <param name="actionStartsWith">Determines whether <paramref name="action"/> is a start pattern.</param>
         /// <param name="includeHistory">Determines whether to include the history of consents.</param>
         /// <returns>Consents matching the parameters.</returns>
-        IEnumerable<IConsent>? LookupConsent(string? source = null, string? context = null, string? action = null,
+        IEnumerable<IConsent> LookupConsent(string? source = null, string? context = null, string? action = null,
             bool sourceStartsWith = false, bool contextStartsWith = false, bool actionStartsWith = false,
             bool includeHistory = false);
     }
diff --git a/src/Umbraco.Core/Services/IContentService.cs b/src/Umbraco.Core/Services/IContentService.cs
index cfc582a5b2..93d51da757 100644
--- a/src/Umbraco.Core/Services/IContentService.cs
+++ b/src/Umbraco.Core/Services/IContentService.cs
@@ -26,7 +26,7 @@ namespace Umbraco.Cms.Core.Services
         /// <summary>
         /// Gets blueprints for a content type.
         /// </summary>
-        IEnumerable<IContent>? GetBlueprintsForContentTypes(params int[] documentTypeId);
+        IEnumerable<IContent> GetBlueprintsForContentTypes(params int[] documentTypeId);
 
         /// <summary>
         /// Saves a blueprint.
@@ -89,12 +89,12 @@ namespace Umbraco.Cms.Core.Services
         /// <summary>
         /// Gets documents.
         /// </summary>
-        IEnumerable<IContent>? GetByIds(IEnumerable<Guid> ids);
+        IEnumerable<IContent> GetByIds(IEnumerable<Guid> ids);
 
         /// <summary>
         /// Gets documents at a given level.
         /// </summary>
-        IEnumerable<IContent>? GetByLevel(int level);
+        IEnumerable<IContent> GetByLevel(int level);
 
         /// <summary>
         /// Gets the parent of a document.
@@ -109,12 +109,12 @@ namespace Umbraco.Cms.Core.Services
         /// <summary>
         /// Gets ancestor documents of a document.
         /// </summary>
-        IEnumerable<IContent>? GetAncestors(int id);
+        IEnumerable<IContent> GetAncestors(int id);
 
         /// <summary>
         /// Gets ancestor documents of a document.
         /// </summary>
-        IEnumerable<IContent>? GetAncestors(IContent content);
+        IEnumerable<IContent> GetAncestors(IContent content);
 
         /// <summary>
         /// Gets all versions of a document.
diff --git a/src/Umbraco.Core/Services/IContentTypeServiceBase.cs b/src/Umbraco.Core/Services/IContentTypeServiceBase.cs
index 17923c61da..c0d5bb96a0 100644
--- a/src/Umbraco.Core/Services/IContentTypeServiceBase.cs
+++ b/src/Umbraco.Core/Services/IContentTypeServiceBase.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using Umbraco.Cms.Core.Models;
 
@@ -50,8 +50,8 @@ namespace Umbraco.Cms.Core.Services
         IEnumerable<TItem> GetDescendants(int id, bool andSelf); // parent-child axis
         IEnumerable<TItem> GetComposedOf(int id); // composition axis
 
-        IEnumerable<TItem>? GetChildren(int id);
-        IEnumerable<TItem>? GetChildren(Guid id);
+        IEnumerable<TItem> GetChildren(int id);
+        IEnumerable<TItem> GetChildren(Guid id);
 
         bool HasChildren(int id);
         bool HasChildren(Guid id);
diff --git a/src/Umbraco.Core/Services/IDataTypeService.cs b/src/Umbraco.Core/Services/IDataTypeService.cs
index 4a765ce384..898b24355e 100644
--- a/src/Umbraco.Core/Services/IDataTypeService.cs
+++ b/src/Umbraco.Core/Services/IDataTypeService.cs
@@ -22,8 +22,8 @@ namespace Umbraco.Cms.Core.Services
         EntityContainer? GetContainer(int containerId);
         EntityContainer? GetContainer(Guid containerId);
         IEnumerable<EntityContainer> GetContainers(string folderName, int level);
-        IEnumerable<EntityContainer>? GetContainers(IDataType dataType);
-        IEnumerable<EntityContainer>? GetContainers(int[] containerIds);
+        IEnumerable<EntityContainer> GetContainers(IDataType dataType);
+        IEnumerable<EntityContainer> GetContainers(int[] containerIds);
         Attempt<OperationResult?> DeleteContainer(int containerId, int userId = Constants.Security.SuperUserId);
         Attempt<OperationResult<OperationResultType, EntityContainer>?> RenameContainer(int id, string name, int userId = Constants.Security.SuperUserId);
 
@@ -85,7 +85,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="propertyEditorAlias">Alias of the property editor</param>
         /// <returns>Collection of <see cref="IDataType"/> objects with a matching control id</returns>
-        IEnumerable<IDataType>? GetByEditorAlias(string propertyEditorAlias);
+        IEnumerable<IDataType> GetByEditorAlias(string propertyEditorAlias);
 
         Attempt<OperationResult<MoveOperationStatusType>?> Move(IDataType toMove, int parentId);
     }
diff --git a/src/Umbraco.Core/Services/IExternalLoginService.cs b/src/Umbraco.Core/Services/IExternalLoginService.cs
index 05f131919e..75f8069f0c 100644
--- a/src/Umbraco.Core/Services/IExternalLoginService.cs
+++ b/src/Umbraco.Core/Services/IExternalLoginService.cs
@@ -15,14 +15,14 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="userId"></param>
         /// <returns></returns>
-        IEnumerable<IIdentityUserLogin>? GetExternalLogins(int userId);
+        IEnumerable<IIdentityUserLogin> GetExternalLogins(int userId);
 
         /// <summary>
         /// Returns all user login tokens assigned
         /// </summary>
         /// <param name="userId"></param>
         /// <returns></returns>
-        IEnumerable<IIdentityUserToken>? GetExternalLoginTokens(int userId);
+        IEnumerable<IIdentityUserToken> GetExternalLoginTokens(int userId);
 
         /// <summary>
         /// Returns all logins matching the login info - generally there should only be one but in some cases
@@ -31,7 +31,7 @@ namespace Umbraco.Cms.Core.Services
         /// <param name="loginProvider"></param>
         /// <param name="providerKey"></param>
         /// <returns></returns>
-        IEnumerable<IIdentityUserLogin>? Find(string loginProvider, string providerKey);
+        IEnumerable<IIdentityUserLogin> Find(string loginProvider, string providerKey);
 
         /// <summary>
         /// Saves the external logins associated with the user
diff --git a/src/Umbraco.Core/Services/IExternalLoginWithKeyService.cs b/src/Umbraco.Core/Services/IExternalLoginWithKeyService.cs
index 1b378491c0..bc31f54f8b 100644
--- a/src/Umbraco.Core/Services/IExternalLoginWithKeyService.cs
+++ b/src/Umbraco.Core/Services/IExternalLoginWithKeyService.cs
@@ -9,18 +9,18 @@ namespace Umbraco.Cms.Core.Services
         /// <summary>
         /// Returns all user logins assigned
         /// </summary>
-        IEnumerable<IIdentityUserLogin>? GetExternalLogins(Guid userOrMemberKey);
+        IEnumerable<IIdentityUserLogin> GetExternalLogins(Guid userOrMemberKey);
 
         /// <summary>
         /// Returns all user login tokens assigned
         /// </summary>
-        IEnumerable<IIdentityUserToken>? GetExternalLoginTokens(Guid userOrMemberKey);
+        IEnumerable<IIdentityUserToken> GetExternalLoginTokens(Guid userOrMemberKey);
 
         /// <summary>
         /// Returns all logins matching the login info - generally there should only be one but in some cases
         /// there might be more than one depending on if an administrator has been editing/removing members
         /// </summary>
-        IEnumerable<IIdentityUserLogin>? Find(string loginProvider, string providerKey);
+        IEnumerable<IIdentityUserLogin> Find(string loginProvider, string providerKey);
 
         /// <summary>
         /// Saves the external logins associated with the user
diff --git a/src/Umbraco.Core/Services/IFileService.cs b/src/Umbraco.Core/Services/IFileService.cs
index 03798c8597..8d68c20c81 100644
--- a/src/Umbraco.Core/Services/IFileService.cs
+++ b/src/Umbraco.Core/Services/IFileService.cs
@@ -36,7 +36,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="filepath">The filesystem path to the partial view.</param>
         /// <returns>The content of the partial view.</returns>
-        Stream? GetPartialViewFileContentStream(string filepath);
+        Stream GetPartialViewFileContentStream(string filepath);
 
         /// <summary>
         /// Sets the content of a partial view.
@@ -57,7 +57,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="filepath">The filesystem path to the macro partial view.</param>
         /// <returns>The content of the macro partial view.</returns>
-        Stream? GetPartialViewMacroFileContentStream(string filepath);
+        Stream GetPartialViewMacroFileContentStream(string filepath);
 
         /// <summary>
         /// Sets the content of a macro partial view.
@@ -118,7 +118,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="filepath">The filesystem path to the stylesheet.</param>
         /// <returns>The content of the stylesheet.</returns>
-        Stream? GetStylesheetFileContentStream(string filepath);
+        Stream GetStylesheetFileContentStream(string filepath);
 
         /// <summary>
         /// Sets the content of a stylesheet.
@@ -179,7 +179,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="filepath">The filesystem path to the script.</param>
         /// <returns>The content of the script file.</returns>
-        Stream? GetScriptFileContentStream(string filepath);
+        Stream GetScriptFileContentStream(string filepath);
 
         /// <summary>
         /// Sets the content of a script file.
@@ -274,7 +274,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="filepath">The filesystem path to the template.</param>
         /// <returns>The content of the template.</returns>
-        Stream? GetTemplateFileContentStream(string filepath);
+        Stream GetTemplateFileContentStream(string filepath);
 
         /// <summary>
         /// Sets the content of a template.
diff --git a/src/Umbraco.Core/Services/IMediaService.cs b/src/Umbraco.Core/Services/IMediaService.cs
index 1ec534029b..ee6ba02b66 100644
--- a/src/Umbraco.Core/Services/IMediaService.cs
+++ b/src/Umbraco.Core/Services/IMediaService.cs
@@ -338,7 +338,7 @@ namespace Umbraco.Cms.Core.Services
         /// </summary>
         /// <param name="filepath">The filesystem path to the media.</param>
         /// <returns>The content of the media.</returns>
-        Stream? GetMediaFileContentStream(string filepath);
+        Stream GetMediaFileContentStream(string filepath);
 
         /// <summary>
         /// Sets the content of a media.
diff --git a/src/Umbraco.Infrastructure/Security/BackOfficeUserStore.cs b/src/Umbraco.Infrastructure/Security/BackOfficeUserStore.cs
index c32362d56c..c91dda8890 100644
--- a/src/Umbraco.Infrastructure/Security/BackOfficeUserStore.cs
+++ b/src/Umbraco.Infrastructure/Security/BackOfficeUserStore.cs
@@ -413,8 +413,8 @@ namespace Umbraco.Cms.Core.Security
             cancellationToken.ThrowIfCancellationRequested();
             ThrowIfDisposed();
 
-            var logins = _externalLoginService.Find(loginProvider, providerKey)?.ToList();
-            if (logins is null || logins.Count == 0)
+            var logins = _externalLoginService.Find(loginProvider, providerKey).ToList();
+            if (logins.Count == 0)
             {
                 return Task.FromResult((IdentityUserLogin<string>)null!);
             }
diff --git a/src/Umbraco.Infrastructure/Security/MemberUserStore.cs b/src/Umbraco.Infrastructure/Security/MemberUserStore.cs
index 3d8f3447d5..87eb5f363e 100644
--- a/src/Umbraco.Infrastructure/Security/MemberUserStore.cs
+++ b/src/Umbraco.Infrastructure/Security/MemberUserStore.cs
@@ -440,8 +440,8 @@ namespace Umbraco.Cms.Core.Security
                 throw new ArgumentNullException(nameof(providerKey));
             }
 
-            var logins = _externalLoginService.Find(loginProvider, providerKey)?.ToList();
-            if (logins is null || logins.Count == 0)
+            var logins = _externalLoginService.Find(loginProvider, providerKey).ToList();
+            if (logins.Count == 0)
             {
                 return Task.FromResult((IdentityUserLogin<string>)null!);
             }