Just installed KDE Plasma on my Ubuntu system to replace GNOME and Wayland. Mainly to get rid of an issue where my games would lose mouse lock, but now I can have two different wallpapers on both monitors and have a clock on my second monitor which is AWESOME.
I WISH I INSTALLED IT SOONER, I LOVE IT.
It (Wayland) is the default session, but supports both for now. OP mentioned they chose the X11 session because games lose mouse lock, which is why GNOME wasn’t an option since it doesnt support X11.
It supports both, but X is going through Wayland, not a direct support. At least that’s how I understand it.