そーす貼っとくか
https://wiki.archlinux.org/title/KDE

引用
To enable support for Wayland in Plasma, also install the plasma-wayland-session package. If you are an NVIDIA user with the proprietary nvidia driver, also enable the DRM kernel mode setting. If that does not work, too, check the instructions on the KDE wiki.

の
plasma-wayland-session
のリンク先はこちら
https://archlinux.org/packages/?name=plasma-wayland-session