Josuke as both Josefumi and himself has manhandled 2 Rock Humans, The Aphex Brothers in his first fight with them as Josefumi in hand to hand combat breaking one’s leg with a kick, and smashing the other's face in with a knee knocking out his teeth and causing him to bleed profusely from it, he will often go for lethal methods such as stated above and stomping on his opponents head, his skill in hand to hand is also a decent edge in this
Josuke as Josefumi and his current self is easily able to heavily harm Rock Humans with his strikes and as Josefumi went for critical attacks such as breaking ones legs and stomping his head, also using his knee to crit ones head, dealing decent damage and breaking his teeth off.
Josuke in himself is also quite resilient in about Chapter 4-6 I don’t recall the exact one he was able to keep throwing about and beating up Ojiro Sesame while poisoned by a venomous red,black and white ringed snake from NA I don’t recall the exact name so I gave all the details
He also seems to be fine for an extended period of time with his liver cut off and still seemed fine although incapacitated by Vitamin C
For the most part I see him doing more damage to Jotaro with his in-character fighting and his superior skills would give him an edge in dodging and countering blows