Inconsistent power levels in superhero films. While it's been a few years since the movies Avengers: Infinity War and Avengers: Endgame came out, it's the one thing that took me out of both movies. Captain America is strong. Thor is stronger. Hulk is the strongest one there is.
If Thanos can mop the floor with The Hulk, Cap should be paste under Thanos. But apparently it's in the script that Cap should get a power boost and go mano-a-mano with the Mad Titan because, well, he's Captain America.
Either that, or everyone had their gamma irradiated Shreddies before the big fight.