Personally, for something like this I’m not sure that getting consensus really matters or is even desirable (death by design by committee is real). Just pick a direction and go. If it’s sufficiently good it’ll catch on and blossom from there, if it doesn’t go back to drawing board and try again.
The problem is that there aren’t even really any attempts out there. The closest as you say are web components, but they’re still extremely primitive relative to something like AppKit or win32.