Should I learn typescript?

I'd recommend you give this article a read, including all the comments. Should help you make a decision.

It will add build time when you run your build command. In the beginning, writing code will be slower, however in my experience the projects you write will move faster overall. There is zero runtime overhead vs javascript because typescript compiles to regular javascript before runtime.

In my view, it's worth it as long as you have Javascript fundamentals down.

YES