There is Xamarin.Forms, which is essentially cross platform XAML with a base set of widgets. It supports Android, iOS, UWP, and they are working on MacOS. No Linux yet.

I wouldn't recommend Forms, I worked with it for about 4-5 months full time last summer and it was unstable and unperformant.

Last summer was a long time ago in Xamarin world. Works pretty well now.

Maybe it was Visual Studio Community that was making it worse, that thing was unstable as hell as well. So much time spent fixing project files...

Forms is the only real selling point for Xamarin. Too bad it doesn't have a good reputation.

The OS API integration, C# and F# are also selling points.

Qt doesn't support even half of the OS APIs that Xamarin does.

As for JavaScript based solutions, I don't intend to ever use it outside the browser.

I have same feelings for js in general, but I suggest you to try React Native. Just follow their official docs/tutorial. I was pleasantly surprised how straightforward it is. I believe you can as well use TypeScript.

I don't see a value for TypeScript outside the browser when I can use C# and F# instead of it.

As for ReactNative, give it two or three years and maybe then I will bother learning it.

As an old dog I have already seen too many carriages pass by, very few of them come back.

You should bother with React Native. It game changer in the mobile world, not a trendy thing that will pass away. Senior iOS devs are going the RN route. Companies all over the places use it for their mobile clients. A little company named WIX recreated its entire mobile front with React Native.

https://www.youtube.com/watch?v=abSNo2P9mMM

I beg to differ. The xamarin stack on Android without forms is much preferable to whatever confused iteration of java+toolchain Google is currently offering.

I'd like to see some benchmark comparisons with electron