Yeah, I still use KDE with X11 because they somehow messed up their window management with Wayland. My problems aren't even about rendering or any those features, but for some reason kwin_wayland's window management is very buggy. I'm still on 6.6 on the distribution that I use, so I don't know if it's fixed in 6.7, but I doubt it since it is here for a long time. Reported it here: https://bugs.kde.org/show_bug.cgi?id=524083