It's not great on Nvidia. KDE's dev team have announced a big Plasma update, specifically focused on Wayland support to be released around February.
I have a 3090 and some stuff works, some stuff doesn't. I am forced to use it because X will lock refresh rates to the rate of the lowest monitor, so my 165hz screens were not being used to their fullest until I swapped over to Wayland which supports multiple monitor refresh rates.
Often I will find system components freezing up. The task bar, for example, will often stop being useable and freeze up. I have had the digital clock widget freeze up on me, which requires a relog to fix. It also doesn't totally work on transparent themes, rendering them without the translucency.