I dislike Electron, the app is heavy and not fan of HTML and CSS. I greatly enjoy using XAML for GUI, building apps in WPF and now UWP. But my biggest problem is I want the app to run on Linux and Mac as well.

Is writing crossplatform XAML apps still not a thing? I heard Microsoft made alot of their software opensource. Can we expect WPF/UWP apps running now on Linux soon? I know W in WPF and UWP stands for Windows, but why not extend it to other operating systems now?