It’s not a situation of either this or that, because these powers do stack up on one another, especially since we’re entering the final saga Sanji and Zoro will probably be Admiral level by the end of this arc, which means they’re one arc away from becoming Yonko level and bonafide top tiers
The only reason why you think Sanji didn’t need the powerup because you think that the peak of Zoro and Sanji come end of the series is admiral level.