For those wanting to build a Wayland-only Linux desktop experience without carrying any aging X11 baggage, GNOME 47 will be able to optionally offer Wayland-only support without carrying X11/X.Org support. This Mutter merge request landed today that allows compiling Mutter with X11 support disabled. That landed today along with this GNOME Shell merge request for being able to disable X11 support too.
How is it relying on XWayland? I don't know of any KDE Plasma components that require X11. The apps you install might need XWayland but that is separate from the Plasma desktop.
Uninstalling Xwayland breaks it, you're greeted to a black background and your mouse pointer.
Additionally, as per their own website, it says "The workspaces have been developed for X11 and much functionality relies on X11. To be able to make proper use of Wayland these bits have to be rewritten."