Sengoku has shown NO durability feats. Granted, he has a mythical Zoan and Zoan Fruits does enhance a characters durability. But Kaido also has a mythical Zoan and on top of that, his skin is hard to damage in base form while majority of the humans (if not every human) can still be damaged by fodder seen with old Whitebeard and Garp (though Shiryu isn't a fodder, he is compared to Admirals-Yonko lvl characters). This by far makes Kaido the most durable character in the whole verse so far. Now imagine if he was like Queen and was also a cyborg? The man would be un-damageable.