I mean, I'm one of the fools who would fool you into thinking it's different, since I use all four languages. ;)

I can just skip the mypy run if I want to do untyped Python. I can't skip adding types if I'm writing TypeScript in most contexts; it's not valid TypeScript syntax. Conversely, I can't add types to JavaScript; it's not valid JavaScript syntax (jsdoc tags and running a static checker over that being a different subject, and more akin to the Python situation).

> how are you actually programming where 90% of the errors/bugs you have are related to types and other things TS addresses

It's the things in the "wat" video. JavaScript, in general, errs on the side of giving you some answer when you try and do something very unusual with types (like add a boolean to a number or a string to an array) over taking a runtime error. TypeScript will fail to typecheck in most of the places where those operations are techincally correct but surprising as hell in the wrong way unless you explicitly coerce the types to match up.