Xwayland is basically Xorg with a Wayland DDX layer -- and it recently got a rootful mode. So that means it's possible to run a complete X desktop, including WM

Xwayland is basically Xorg with a Wayland DDX layer -- and it recently got a rootful mode. So that means it's possible to run a complete X desktop, including WM, on top of a Wayland compositor. However, the drawback is that with the exception maybe of Weston, one does not simply start up a Wayland compositor. You need to have support for logind seats and that sort of thing. So unless you want to spend an afternoon assembling the components like a piece of flat-pack furniture from Target, you basically need systemd and a distro that bundled those components for you the right way.