[mutagen]

Have you looked at Uno?

http://platform.uno/

C# & XAML UWP layer with Xamarin for mobile. The company behind it has been using for a few years to produce apps and recently open sourced it. I'm intrigued and weighing it against Flutter for my next bit of mobile experimentations.

[krzat]

This thing seems to be a layered cake of leaky abstractions. Flutter is actually the opposite.