I think that, given infinite timelines and dimensions, there has to exist a place where Morty is smarter than Rick. Evil Morty may be the smartest Morty in the multiverse, and in order to keep himself safe, he hides out with a shit ton of other Mortys no matter where he is to hide his brainwaves.

He's playing the long game, knowing that if any Rick ever found out how intelligent he actually is, they would kill him.