Hello,
Gnome extensions will only work on Gnome.
Wayland gestures in KDE Plasma will only work under Wayland session.
If X11 gestures are not satisfying then you can try touchegg
package and then consult this project that adds that functionality to KDE Plasma GitHub - NayamAmarshe/ToucheggKDE: TouchEgg configuration for MacOS and Windows like Touchpad Multi-Touch Gestures on KDE Plasma. regardless the session.
To have access to Wayland session in KDE Plasma you need to install plasma-wayland-session
. It should also install the dependencies if are missing, but you have to enable early kms for your nvidia drivers. This should help you with that