ENTJ - Te - Ni - Se - Fi
ESTP - Se - Ti - Fe - Ni
ENTP - Ne - Ti - Fe - Si
So, ENTJ and ENTP both share 2 functions in common with ESTP, a piece. But, say we rule out inferior function cus they're.....inferior.
ENTJ - Te - Ni - Se -
ESTP - Se - Ti - Fe -
ENTP - Ne - Ti - Fe -
Then, ENTP comes out the winner in terms of # of commonalities. Ti/Fe sharing, while ENTJ only shares the Se.
I think it also depends on what enneagram they share.
Anecdotally, as fleshed out individuals and not just pieces of functions, I've found that the ESTPs I know look more similar to me than they do to ENTJs I know. This interpretation is again limiting because it's an individual by individual case.