This is the original developer/maintainer of Sway and Wlroots’ opinion on NVIDIA with regard to Wayland. This doesn’t seem like an unfair opinion to me. Gamescope breaks regularly due to bugs in NVIDIA’s proprietary driver; even if they know what the issue is, they can’t send patches to fix it because it’s proprietary. The best they can do is open a bug and beg them to fix it, which is what they do. If there’s an issue on Intel or AMD, they can just send patches upstream to Mesa, and I would guess they do.
Mind you, I’ve actually had a better experience on KDE Wayland than Xorg. Categorically…with the exception of Steam. While the games themselves play fine, the client is very glitchy. But it’s a small price to pay for all the other nonsense I’ve had to deal with on GNOME/KDE X11.