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.