I've had people argue with me for literal hours that he isn't one though lmfao, are they actually reading the series?! He comes from a fucking samurai dojo he was raised in, trained by them, is called Mr Bushido by Vivi and uses katana! Also has Buddhist beliefs and uses Japanese named attacks for some of his attacks like Rashomon! (Which has huge symbolism I believe too? Like those gates Orochimaru summoned before and the movie too ofc?)
I will gladly die on the hill that Zoro is a freaking samurai and is from Wano too as well, even if he can't be from there directly, he blatantly is by heritage or so.