Naturally speaking he should top out at maybe War arc SM Naruto, or maybe KCM Naruto at the very most. Boruto surpassing KCM Naruto while not being a child of prophecy, not having Kurama hax, and not being a transmigrant of Ashura would be dumb as hell. But given the power-ups Boruto's been effortlessly given at this point with a possible Tenseigan, and a cursed seal, it could sadly happen eventually.