After the update that was released on 4 August, this is still unresolved, but it has changed, indicating that Oracle may be working on it. Whereas before, when a VM went to full screen during a Wayland session, it would immediately lock up, and be unresponsive. Since, at full screen, it then covered the host's display, the host was also locked up, for all practical purposes.

I don't know whether I've mentioned this before, but in a Wayland session, I can successfully maximize a VM within the host window's client area. This does not lock up the VM or the host, but it's still not full-screen. And some distros/DEs do not automatically resize to fit within that client area, but display scroll bars instead, making it very difficult to use both OSs without a lot of manual scrolling.. Solus MATE is an example of that.

Now that Solus 4.4 has been released, and I still cannot take a VM to full-screen while in a Wayland session, I thought I'd ask about it again here.