I didnt Say he was more durable than kaido only compared how his durability work so that its easief for you to understand.
Garp unlikd kaido isnt natural6 durable.
He need haki.
By the way what do you disagree about? That shiryu piercing Garp wasnt hyped? And a good feats? Expecialy when its Garp who is know to have fought Roger a swordsman in the past.