The word "meritocracy" was invented for a book about how it's a bad idea that can't work, so I'd recommend not trying to have one. "Merit" doesn't work because of Goodhart's law.
I also feel like you'd never hire junior engineers or interns if you were optimizing for it, and then you're either Netflix or you don't have any senior engineers.
FWiW Michael Young, Baron Young of Dartington, the author of the 1958 book The Rise of the Meritocracy popularised the term which rapidly lost the negative connotations he put upon it.
He didn't invent the term though, he lifted it from an earlier essay by another British sociologist Alan Fox who apparently coined it two years earlier in a 1956 essay.
I also feel like you'd never hire junior engineers or interns if you were optimizing for it, and then you're either Netflix or you don't have any senior engineers.