Another example for a 10x developer would be fabrice bellard. I've participated in this year's advent of code and usually needed dozens of minutes if not hours to solve examples. Then you see some of the videos from streamers on the leaderboard. they just quickly type out code. Sure, I hadn't practiced much and they had a lot of practice (doing AoC was my attempt of getting some), but they are definitely a two digit multiplier away from my performance. Of course, this doesn't directly translate to performance on the real job though, but there is a correlation I'd say.

Example video: https://www.youtube.com/watch?v=YKpViLcTp64