Doesn't really work like that in Wayland. If an application framebuffer is full screen and in a compatible pixel format the compositor can do "direct scan out"

Doesn't really work like that in Wayland. If an application framebuffer is full screen and in a compatible pixel format the compositor can do "direct scan out" where the compositor sends the framebuffer directly to the crtc instead of compositing first. I know that wlroots supports that. I'm not sure how much performance it saves to be honest. And I'll second that most commercial games do go through XWayland, though it depends on what games you like!