Microsoft doesn't commit to UI frameworks in any language. By contrast, DirectX 11 and 12 (and Direct2D) are C++-native and have become core modules within NT. I don't think MS has abandoned C++, but the use case for C++ has shrunk considerably since the 1990s

If you go into Visual C++ developer blog, you will notice it has been all about Unreal support during the last year, and not much else.