We don't really know as PS5 seems to have good headroom in the native 4K mode. They had to search for one rare drop at 2088p in the most hecti conditions (remember the game could drop to 20fps on mid-gen consoles), the vast majority of the time the game is native 2160p locked 30fps.FYI 4k is checkerboarded from a native resolution of 1527p.
Full graphics mode would need to be around 1250p60 in this game, as it roughly takes 3x the GPU power to double a games framerate.
And you can't really use the CBR mode for the hypothetical high quality 60fps mode as CBR and native 4K modes have different settings.