I did a fast test on my Recalbox gaming setup but it failed to find the X or wayland libraries. I'll do a more detailed test on the Raspbian OS setup in the next days.
I did a test today and it seems to work for 2d and 3d views. It's no test for performance yet. Just a confirmation it's possible. Default Godot 4, X output works. I tried wayland support from 4.3, but that didn't start.