One important thing to keep in mind about the "10x engineer" is that it is a largely manufactured concept that originates with Steve McConnell, the author of Code Complete. He read a study from the 1960s that showed productivity variations between programmers and concluded that there was a 10x productivity difference "between the best and worst engineer."

Since popularizing the concept by naming his consulting company's blog "10x" (which he no longer does) he has had to defend this over and over again because there actually is only flimsy research (at best) to support the idea. For example, McConnell admits that the study he based the idea in "found no relationship between a programmer’s amount of experience and code quality or productivity." (See https://www.construx.com/blog/productivity-variations-among-...).

The book "Leprechauns of Silicon Valley" (https://leanpub.com/leprechauns) further undermines the idea.