Mypy is just okay. Haven't used TS to know the dark corners there, but any type system that's bolted on to the language is going to have dark corners in the best case.

It's better than no type system, however. I remember when typed languages were "bad" because it "slowed you down" and "wasn't necessary if you know what you're doing"... how naive I was when I repeated those words so many years ago :)