Not at all. FAANG is just a convenient and geographically comparable reference point. I have no trouble finding non-FAANG UK developer jobs online that pay more

Not at all. FAANG is just a convenient and geographically comparable reference point. I have no trouble finding non-FAANG UK developer jobs online that pay more than ~$65k/year and neither should you. I'm not deeply familiar with babel, but I'm pretty sure that if you can lead that project (which should involve a fair amount of in-depth knowledge about JS, coding chops and CS knowledge) you will have many options to earn in excess of $65k anually.