You've moved the goalposts on this argument now. "$Thing is hard to implement on Wayland and requires quite a lot of effort by each DE"[1] is a very different argument to "$Thing doesn't work on Wayland". Pretty much everything you listed works well in Fedora with Gnome/Mutter.
If the maintainers of the DEs are happy with the effort, then I don't see a problem? (unless you're a DE maintainer, in which case - fair enough).
[1] When I first wrote this sentence I wrote "X is hard to implement" using X as a metasyntactic variable before I realised that was incredibly confusing in context!
You forgot to mention that it doesn't work without portals and Pipewire dependency, and portals have to be implemented individually for each DE.
> I use global hotkeys to switch between keyboard layouts, see the screenshot. Works fine.
Because the KDE developers went to a lot of effort to make it work. That doesn't mean it will work well in other DEs and that is Wayland's problem.