Controllerless EPiServer how to?

Hi,

I've tried to follow this code to implement Controllerless EPiServer.

https://swapcode.wordpress.com/2018/05/16/episerver-block-performance-with-controller-vs-without-controller-vs-irendertemplate/

In short:

public abstract class ViewRenderTemplate<T> : IView, IRenderTemplate<T> where T : class, IContentData ...

When implementing this abstraction:

[TemplateDescriptor(Default = true, AvailableWithoutTag = false)]
public class StartPageViewRender : ViewRenderTemplate<StartPage>
{

I have tried a lot of options for the "TemplateDescriptor" attribute, but nothing seems to work.

With Tags, without Tags, with TemplateTypeCategory, with typeof(StartPage) as model type etc etc.

Have I missed anything?