[EFLKumo]

Making a XAML UI is fundamentally authoring a WinRT interface, I guess. And for cppwinrt, Microsoft's solution is like describing in so-called MIDL .idl files, compiler generating cpp stubs, copying these stubs and filling in implementations. After static reflection introduced in cpp idk if this process could become better, but Microsoft just left cppwinrt in maintenance mode, it's impossible I guess.

On the Rust side, IMO the windows-rs even has not thought about authoring new com interfaces, only consuming or impl-ing existing ones. In fact the experience of consuming windows apis in rust feels good if one would like to get rid of C++. Rust with NAPI or BoltFFI etc. offers an maintaining-friendly option for cross-platform app authors to interact with the OS more deeply. So in conclusion the situation right now is that windows apis just become not so unapproachable, while in-depth things keeping comfortable only with C# or .NET.