Popper’s criticism is, iirc, drawn mainly from Plato’s Republic. But Popper somehow managed to read a deeply ironic and subtle text as a recipe for tyranny. Eg there are numerous points where Socrates makes obviously bad arguments which others call out, and Socrates just hand waves them away. Numerous critics and philosophers have made this observation, the most ready to hand example I can find is here: https://www.theguardian.com/commentisfree/2012/may/10/empty-...
It is a simple, massive, and all too common blunder of interpretation to read the Republic the way Popper does.