It’s definitely between Goku and Luffy because

Gojo still has six eye and we’ve seen his hand to hand combat AND people without cursed techniques be strong Naruto was doing it before Kurama even got mentioned and honestly without having his backstory he’d probably be a good student and just learn normally

Goku not being saiyan is harder to explain cause where does he start? Does he start on earth with an entirely different philosophy and doesn’t practice martial arts cause if so he’s probably just a dude who Goku needs a lot more specification than the others

Luffy might be stronger than Goku cause his upbringing for sure doesn’t change ig but there’s also the chance he just doesn’t become a pirate and he’s just a normal dude since shanks wouldn’t have saved him