Why wasn't he eligible?
Who is the Olympian he ragdolled? I'm assuming it was one of the Swedes on the national circuit. Now Sweden does actually have some legit wrestling credentials relative to its population size, though they are primarily in Greco-Roman and not Freestyle.
This is downright misleading. Yes, he won a bronze medal in freestyle wrestling at the junior level competing against other teenagers. Now yhis is no mean feat, as the talent pool in Russian wrestling is incredibly deep even amongst the youth and many of the kids go on to become monsters on the Olympic scene (they have to start somewhere obviously). But it's not uncommon for the level of competition to increase exponentially as the age group does: like you said, wrestlers get better in their late teens and early twenties. It's also a total supposition on your part that the guy who defeated him as a teen went on to medal at the Olympics. It may not have even been the guy who took gold at the tournament for l we know.
But I digress. I have no issue with the idea with Khamzat making it to the Olympics had he decided to devote himself to Freestyle Wrestling instead of MMA. He was clearly dominant enough and had the pedigree and dominant wins on the national circuit. I dunno if he would represent Sweden though and frankly there are tons of other talented wrestlers from Russia competing for that slot.
However, assuming blindly that his ceiling is earning a medal or better based on what we've seen is crazy IMO. There are too many levels to such a specialized and dedicated, intensive sport. Could he? Absolutely, the guy is talented. But he would be competing against absolute monsters from all over the world, many of which have better wrestling accolades than his own. Cox is one of them.