Describe the bug

I was used to have custom TypeConverter to convert complex types from/to strings
It was working when the serializator was Newtonsoft, now that you moved to internal dotnet serializator it doesn't work anymore

To Reproduce

Create a controller that returns a class with a complex type where you implemented a TypeConverter for (and registered using TypeDescriptor.AddAttributes )
Look the result of the controller and you'll see that the output will not be serialized according to the TypeConverter but will be serialized fully as a complex object

We will close this issue if:

• the behavior will be consistent with newtonsoft serializator behavior

Further technical details

• tried on ASP.NET Core version 3.1

Note that using the package Microsoft.AspNetCore.Mvc.NewtonsoftJson and doing services.AddControllers().AddNewtonsoftJson() (so basically restoring newtonsoft serializator) fixes this problem (basically bypass internal json serializator)