I very strongly disagree with this. Typescript is a lifesaver on a non-trivial React codebase. Writing correct code is hard and you need every advantage you can muster. Type checking is an important part of that.
Look into nullish coalescing and optional chaining.
Sure, vanilla JS or react doesn't help with using a var as a function, but I can probably count on my left hand how many times I tried to do that. That doesn't warrant a completely new language.
ps.: typeof is also a thing in vanilla JS
