Luffy didn't fight in G4 for hours, in any case I wasn't say Zoro needed maximum effort, merely this is evidence he was engaged in a moderately strenuous 2vs1 for some period of time.
Apoo was already on his back foot unbalanced against Drake and had both his weapons and attention occupied. This feat is meaningless considering the damage wasn't even enough to put Apoo down for a whole chapter, this is while Apoo is being nerfed and not using his fruit due to a bad 2vs1 CQC matchup while being chased by others.
Zoro>Apoo, no doubt, but this was an unfair fight and was not a "low diff" win in a fair 1 vs 1 as Zoro fans seem to be memory holing.
Zoro is good at dragging his captain down and preventing him from reaching the roof.