I would like to take this opportunity to recommend that everyone who is into C#/.NET Core and high-performance Windows UX development take a look at the following: https://github.com/prasannavl/WinApi

I was able to get a workable demo app going in just a few minutes using their Win32 approach. Seems very promising to me for purposes of building native-levels of performance into windows apps using managed C#. The performance statistics published on the repository seem fantastical, but I can believe it now that I've played around with a few of their demos.