Wayland is an intended replacement for X11 for the common case of a desktop Pc where apps are running on the same Pc as the display. Xwayland is then provided for the traditional use case of X11, that of client and display on distinct machines. There is a good talk by a developer on Wayland, who worked in X11 in the past, explaining how most of X11 is redundant in the modern setting, and how one can do better by stripping the display architecture down to only what is needed. GnomeDesktop and KdeDesktop now use Wayland, except on Pcs that use nVidia graphics (for now).

Wayland uses OpenGl hardware to composite windows.

WestonCompositor

There is a reference compositor called Weston. To build it, one uses meson. If pipewire is not present, you tell this to meson via

meson build/ -D pipewire=false
and then build with
ninja -C build/