10x makes sense only in terms of specific technology platforms.
I'm a 10x programmer at building Django apps compared to a developer who has never worked with Django before.
Someone who developers against WordPress on a daily basis will easily 10x my own attempts at building things on that platform.
I don't think it's only about specific technologies. I have occasionally worked with someone who was 10x (or more) the average in the org, and it wasn't just producing new code: it was debugging faster, reviewing faster, providing an insight to another dev with a moment's thought that unblocks their whole sprint, and, yes, still producing many times as many PRs as typical. In a modern corporate environment, the main problem is giving such a person enough to do in enough variety so that they don't get bored.