EXWM does some special stuff though. It maps X11 windows in a way that they appear to be Emacs buffers and are managed as such. It also optionally captures certain input from them so that Emacs sequences (for example stuff prefixed by C-x) still work as usual. All this is done in a very granular way to maintain the illusion. So for example if I hit "b" after "C-x" or while the Emacs minibuffer is active then it goes to Emacs but otherwise it goes to the application. And generally it works very well, I've been using it for many years.

To do this in Wayland I imagine we'd need to have Emacs act as the compositor and that sounds a bit too crazy... Or perhaps some kind of a proxy-compositor could be used that could be fully driven by Emacs using an rpc protocol. Is there such a thing out there?