Sacrosanct
Legend
Their methods may be arcane but their achievements are only what mundane people can achieve.
What? This doesn't make sense
Only with HP as meat, which they patently are not. They must also reflect that highly skilled individuals are adept at not being hit as well as hitting more & harder.
Bottom line is that a 3rd level barbarian can take more punishment than a rhino can, no matter how you look at it. Damage resistance isn't "harder to be hit", it's "shrugging off blows that land". And a GW Barbarian also probably has a better AC and damage output than a rhino. So no, a "highly trained" regular real life person cannot take out a rhino in melee combat, or take as much punishment as a rhino. Nor can they take out a grizzly bear or similar.
I know gladiators did this but I can't find the details (they may have always had numbers in their favour)
They are all navy seals. Exceptional specimens but still "normal" in the sense they really exist. (Parkour & Backflips in general are things that seem to transcend anything I can imagine being able to do )
Navy seals aren't exceptional, but merely highly trained (by your categorization)? I've met several of them. They are very much what I'd consider the best of the best. The exceptional. The pinnacle of human achievement. So by your logic, that's level 5-9. Which makes them as tough as a large freaking dinosaur?
Sorry, but I don't know any human who is equivalent in melee combat as an allosaurus or ankylosaurus. When you look at what a level 1-4 PC can take out and/or do, they are very much the elite of what a normal person could do. In fact, I'd even posit that level 3 and 4 get into superhuman realms, because there's no way any human alive today can do what a level 3 or 4 fighter/barbarian can do.