I agree that TypeScript is great, but I've seen it used to establish its own kind of technical debt is what I'm trying to say. If you establish types for your poorly designed application it will only entrench bad design deeper. So, throwing a type system at that problem isn't actually helpful at all in cases like that.
I agree though that using TS and not worrying about actually defining types can be great. I do think you can run into sort of wandering inference bugs or cases where other peoples' types can be poorly defined, but that's a rare problem in my experience and well worth the benefits you get otherwise.
Anyway, I'm definitely not trashing TypeScript or suggesting no one should use it or anything. I almost always start new projects with it.
Keep in mind, at my current company we don't use it (giant 5 year old AngularJS codebase) but I would love to.
You don't even have to use it fully. Just mark your function arguments and you're already saving headaches.