I’m on KDE Plasma with Nvidia and Wayland with the proprietary 530 drivers but really the experience (due to Nvidia’s own fault) doesn’t feel polished at all although it’s very smooth, but the fact of having to be constantly switching between Xorg and Wayland because one or another program doesn’t behave the way it should in Wayland (frameskipping, blank screen, tearing) and I was thinking if using the open source drivers could fix something or make it worse.
I remember testing the open source drivers some time ago and running the Terraria compilation for Linux was not working well at all, and that being a native Linux compilation, maybe the Proton version would have worked better.
Unless you have a Geforce 7xx or older it is still very bad as Nvidia is preventing the open-source drivers to work properly on newer cards with their cryptographically signed firmware.