Hello, arch user here. I have noticed that plasma desktop and kwin consumes a lot of gpu usage just by itself, even if the compositor is disabled (but to a lesser degree). Kinda as shown here
nvidia-smi pmon shows results like this:
Idx # C/G % % % % name
0 324190 G - - - - Xorg
0 324263 G - - - - kwalletd5
0 324327 G - - - - ksmserver
0 324331 G - - - - kded5
0 324332 G - - - - kwin_x11
0 324369 G 33 12 - - plasmashell
0 324418 G - - - - polkit-kde-auth
0 324423 G - - - - xdg-desktop-por
0 324574 G - - - - kclockd
0 324576 G - - - - kdeconnectd
0 324600 G - - - - kaccess
0 324613 G - - - - DiscoverNotifi
The display is 1440p 144Hz. Plasma is 5.27.8