Well it also absorbs sharb force its a matter of strength there Zoro easily cut through steel while Sanji failed to break the door
A fodder is Sheepshead
No. Zoro's feat was a matter of lethality, not force. Steel is nothing for a seasoned swordsman lol. Even Kinemon can do that.
Eg. Doffy would have sliced that door like butter, because his strings are extremely sharp.
Hell it's even comparable to Kaido. Kaido eats blunt attacks like nothing, even falling from a height of 10k ft. But Oden cut Kaido's chest open.