diff --git a/src/Umbraco.Web.BackOffice/Controllers/BackOfficeServerVariables.cs b/src/Umbraco.Web.BackOffice/Controllers/BackOfficeServerVariables.cs
index 0a8606f01f..1e2e986413 100644
--- a/src/Umbraco.Web.BackOffice/Controllers/BackOfficeServerVariables.cs
+++ b/src/Umbraco.Web.BackOffice/Controllers/BackOfficeServerVariables.cs
@@ -210,7 +210,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
                         },
                         {
                             "iconApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<IconController>(
-                                controller => controller.GetIcon("")!)
+                                controller => controller.GetIcon(string.Empty))
                         },
                         {
                             "imagesApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<ImagesController>(
@@ -266,7 +266,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
                         },
                         {
                             "memberApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<MemberController>(
-                                controller => controller.GetByKey(Guid.Empty)!)
+                                controller => controller.GetByKey(Guid.Empty))
                         },
                         {
                             "packageApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<PackageController>(
@@ -274,7 +274,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
                         },
                         {
                             "relationApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<RelationController>(
-                                controller => controller.GetById(0)!)
+                                controller => controller.GetById(0))
                         },
                         {
                             "rteApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<RichTextPreValueController>(
@@ -358,7 +358,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
                         },
                         {
                             "languageApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<LanguageController>(
-                                controller => controller.GetAllLanguages()!)
+                                controller => controller.GetAllLanguages())
                         },
                         {
                             "relationTypeApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<RelationTypeController>(
@@ -378,7 +378,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
                         },
                         {
                             "imageUrlGeneratorApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<ImageUrlGeneratorController>(
-                                controller => controller.GetCropUrl(string.Empty, null, null, null)!)
+                                controller => controller.GetCropUrl(string.Empty, null, null, null))
                         },
                         {
                             "elementTypeApiBaseUrl", _linkGenerator.GetUmbracoApiServiceBaseUrl<ElementTypeController>(
diff --git a/src/Umbraco.Web.BackOffice/Controllers/DashboardController.cs b/src/Umbraco.Web.BackOffice/Controllers/DashboardController.cs
index 8599adaedc..44b4551eda 100644
--- a/src/Umbraco.Web.BackOffice/Controllers/DashboardController.cs
+++ b/src/Umbraco.Web.BackOffice/Controllers/DashboardController.cs
@@ -80,8 +80,13 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
         // TODO(V10) : change return type to Task<ActionResult<JObject>> and consider removing baseUrl as parameter
         //we have baseurl as a param to make previewing easier, so we can test with a dev domain from client side
         [ValidateAngularAntiForgeryToken]
-        public async Task<JObject> GetRemoteDashboardContent(string section, string baseUrl = "https://dashboard.umbraco.com/")
+        public async Task<JObject> GetRemoteDashboardContent(string section, string? baseUrl)
         {
+            if (baseUrl is null)
+            {
+                baseUrl = "https://dashboard.umbraco.com/";
+            }
+
             var user = _backOfficeSecurityAccessor.BackOfficeSecurity?.CurrentUser;
             var allowedSections = string.Join(",", user?.AllowedSections ?? Array.Empty<string>());
             var language = user?.Language;
@@ -141,8 +146,13 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
         }
 
         // TODO(V10) : consider removing baseUrl as parameter
-        public async Task<IActionResult> GetRemoteDashboardCss(string section, string baseUrl = "https://dashboard.umbraco.org/")
+        public async Task<IActionResult> GetRemoteDashboardCss(string section, string? baseUrl)
         {
+            if (baseUrl is null)
+            {
+                baseUrl = "https://dashboard.umbraco.org/";
+            }
+
             if (!IsAllowedUrl(baseUrl))
             {
                 _logger.LogError($"The following URL is not listed in the setting 'Umbraco:CMS:ContentDashboard:ContentDashboardUrlAllowlist' in configuration: {baseUrl}");
diff --git a/src/Umbraco.Web.Common/Extensions/LinkGeneratorExtensions.cs b/src/Umbraco.Web.Common/Extensions/LinkGeneratorExtensions.cs
index 71f1d5410a..627778eb2f 100644
--- a/src/Umbraco.Web.Common/Extensions/LinkGeneratorExtensions.cs
+++ b/src/Umbraco.Web.Common/Extensions/LinkGeneratorExtensions.cs
@@ -54,7 +54,7 @@ namespace Umbraco.Extensions
         public static string? GetUmbracoApiService<T>(this LinkGenerator linkGenerator, string actionName, IDictionary<string, object?>? values)
             where T : UmbracoApiControllerBase => linkGenerator.GetUmbracoControllerUrl(actionName, typeof(T), values);
 
-        public static string? GetUmbracoApiServiceBaseUrl<T>(this LinkGenerator linkGenerator, Expression<Func<T, object>> methodSelector)
+        public static string? GetUmbracoApiServiceBaseUrl<T>(this LinkGenerator linkGenerator, Expression<Func<T, object?>> methodSelector)
             where T : UmbracoApiControllerBase
         {
             var method = ExpressionHelper.GetMethodInfo(methodSelector);