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.