I know close to nothing about MMA, so even after watching “Born a Champion” (2021), I still have no idea whether I was watching a based-on-a-true-story sports flick or a movie that was just pretending to be one. I do know “Born a Champion” is a pretty lame title. I also know MMA fans will probably like this film because there’s enough fighting (eventually) and famous MMA people (I think) in it. Otherwise, it’s a patently mediocre story following a well-worn, Rockyesque formula. Ex-Marine, hard life, fighting for his family, fighting because that’s all he knows, predictably bloody hijinks ensue.