Not counting the Steam Deck, since KDE isn’t actually turned on while you’re running games.
Normally I’m a Gnome guy, but I’m building a tiny low power portable computer and wanting to keep resource utilization low, so I’m investigating other options.
gnome with “dash to panel” and “arc menu” extensions. familiar and unobtrusive, but seemingly resource heavy. for a low spec machine, my vote would go to xfce.