- Edited
Woah ... this is even better! For a long time I've needed to use X11 in order to take VMs to full-screen (HOST+F). Recently I learned of a work-around involving turning off the mini-toolbar in the VirtualBox settings (the one at the bottom of the list). That's not a critical feature, so it was better than nothing.
After seeing that there's almost no screen flicker anymore with Wayland on this laptop, I decided to try adding that mini-toolbar setting back to a VM (a Plasma VM for testing Discover), and seeing if it would still lock everything up if I switched to full-screen on Wayland. Turns out, that's fixed, too. Here's that VM on a wayland session on this laptop. And absolutely zero locking up, as you can tell from the items I've launched, including Spectacle, which I used to snap this screenshot.
Now I've got some work-arounds to remove from a bunch of VMs. Just don't need 'em anymore. And to be perfectly honest, I have seen a couple of brief flickers since I wrote the first post about this. But they were trivial, lasted for less than a second, and I have no idea whether they're related to the earlier phenomenon. Again, they're nothing that will keep me from using Wayland full-time on all the machines here.