As I’m on the unstable branch I can tell you that Plasma 6.1.4 + Wayland + Nvidia 555 was still a bit glitchy.
Today with the update to Nvidia 560, the remaining glitchiness I experienced seems to be fixed, but it’s only been a couple of hours if that, and I haven’t tested it with an X11 session yet.
Now for anyone with nvidia cards that aren’t supported with the new driver will almost certainly have a less than optimal experience (especially on Wayland), not sure how it’s going to be handled.