Hm? I thought MAUI was the multiplatform UI toolkit and WinUI 3 was the native Windows 10 UI toolkit (evolved from UWP) repackaged for bundling with each app?
I hope I do not destroy the dreams of someone.
You kinda did. :)
I was trying to grok the point of Uno if WinUI was truly multi-platform in the MacOS/Linux/Android/iOS sense.
If you care about user experience - writing it for each platform would have ended up being faster in the last app I did with flutter - so many subtle things that dragged the development out for weeks where as native had all these things working out of the box. I haven't worked with Xamarin in a while but I remember the quality was the worst out of all solutions I've used. So many moving parts, "this works in the latest version" and then half of other dependencies haven't been updated, and you just said the same thing.
Since WinUI 3 is multiplatform (in conjunction with the first party Linux/Android and OSX/iOS support in .Net 5 and 6, and with MAUI), Uno no longer needs to exist outside of dealing with legacy UWP code (which, as per Microsoft rules, shall never die).
Also, re: web UIs, I hate to inform you, but everyone hates these. They are slow, clunky, optimized for all the wrong things, inconsistent, and sometimes ugly. The move to HTML canvas-based UIs in otherwise native apps Android and iOS is why most apps on phones are slow, even though a purely native one would have been fast on an ancient phone. Please do not repeat this mistake.