Yes - there are some pain points - but my experience is that the 2x is worst case. It gets MUCH closer to 1x with experience, and I'd dare to say it will be closer to 0.75x over the long term.
As soon as a significant portion of the time spent tackling a new feature or addressing a bug becomes reading code (which you may not have written) the types pay off to at least[1] a 0.75x time-multiplier, and I'd say that's very conservative. It also makes it a hell of a lot easier and faster to collaborate on different parts of a feature that interact without exactly overlapping—"here's the interface I expect to implement, code to that, if anything changes TypeScript will tell you without our even having to talk (about that)"
