Nah, RO was sent flying 15 feet off of pillar from a kick to the head. That should've killed any human, so clearly he has above human level durability and decisively so. In the same fight he was thrown at least 20 feet in the air.. and again bouncing off a pillar and wasn't KO'd. Besides, Cap couldn't even unleash that kind of punch in a combat situation. It's like people that claim Drago punches at 1850 PSI during a fight. Um no, that was done to a stationary target, not moving, not able to roll with the punch or avoid it, he set himself and took a deep breath and then gave it all he had. That isn't comparable to a boxing match at all. Same thing here, sure if Cap was allowed to stand there like Drago, set himself, prepare himself and unleash everything he had to one of them and they don't move... Sure, he might be able to one shot them... That isn't how a fight works though.