What are your opinions about Avalonia? It runs on Windows, Mac, Linux, Android, iOS and WebAssembly, with the mobile platforms being in a more immature state as support was added recently.

MAUI is the continuation of Xamarin.Forms, while Avalonia is the spiritual successor to WPF, albeit open-source and cross-platform. MAUI uses platform-native controls (which means the same control may appear or behave differently between operating systems), while Avalonia builds everything with Skia, so it renders the same in every platform. I think of it as the .NET alternative to Flutter, though with a more desktop-centric focus, instead of being mobile-first.

I have not used it yet but it seems the most promising .NET UI framework and I'm hoping to build a personal project in the following months. The first Release Candidate of Avalonia UI v11, which stabilises the API, was released two weeks ago.