I will try to attempt to address some of your concerns...

"First they focused on making .NET Core all about ASP.NET with a clear focus on MVC and making everything super granular. Then they didn't like how granular it was and started to put lots of featurs into smaller pacakges again."

.Net core was a ground-up re-write and was the vehicle used to opensource all .Net. It was always meant to grow into a full-scale offering and eventually bring along all the features users demanded. I personally love reading all the fun library code: https://github.com/dotnet/runtime/tree/master/src/libraries

" First introduce Newtonsoft Json into the default .NET Core stack. Then rewrite everything."

Newtonsoft itself is bloated and there is no turning back for that library. MS is providing an option to use a lightweight JSON library that uses the new SPAN ref struct.

"The ASP.NET Core team now is realising that people hate MVC and they are splitting out more features from MVC into more basic ASP.NET Core features, which is why routing has completely changed again with endpoint routing."

Endpoint mapping wasn't born out of hate for MVC, it facilitates the separation of framework/transport/protocol without introducing config files (or handler code) for each. https://github.com/aspnet/AspNetCore/issues/4772

"The reason for all of this is old MSFT thinking. It's not bloody rocket science, people have been saying it for years that they don't want to be forced into MVC, they want things to be more lightweight, bla bla bla."

Maybe I am old but I remember when MS was almost forced to adopt MVC. They kept webforms alive for a long time. They introduced razor pages when SPA world demanded an easier solution. I am not sure if there was going to be a way to satisfy everyone here.