I'm still cycling through wayland and x11, and I also do get 1.5 hours more runtime on average on my old 2nd gen t14s with x11+xmonad+no compositor. It's one of the main reasons I'm struggling to move permanently, as I really don't see any advantage from my perspective as I don't use any desktop environment or feature that would make a compositor actually useful. The only thing I do notice occasionally are black borders due to shadow dropdowns in gtk4 programs that don't respect the system theme I've set.