No need to register controllers into container, DefaultControllerActivator works fine.

src/Umbraco.Web.UI.NetCore/Program.cs

@@ -21,9 +21,8 @@ namespace Umbraco.Web.UI.NetCore
                     x.ClearProviders();
                 })
                 .ConfigureWebHostDefaults(webBuilder => { webBuilder.UseStartup<Startup>(); })
-                // TODO: MSDI - this should probably be on one day, more so when we can reduce the number
-                // of times we build a ServiceProvider from services collection
-                // right now it's just painful.
+                // TODO: MSDI - this should probably be on one day
+                // First we need to resolve the composition conditional registration issues see #8563
                 .UseDefaultServiceProvider(options => options.ValidateOnBuild = false)
                 .UseUmbraco();
     }