when comparing these two anime series that stands as the root to shounen anime. one must want to compare the level of strength at which these two are.
the major thing that the Naruto verse has going for it is their form of energy (chakra) because if these there are the existence of tailed beast and summoned beasts, and the eyes of the Uchiha clans all these are the major reason why the naruto verse is more powerful than one piece's.
but for a long time now I've seen how underrated one-piece characters are when compared to naruto's there are a lot of shortcomings as to how these two anime are graded.
what makes one-piece characters strong is the existence of Haki and devil fruit yet not all characters have this devil fruit, as it is not a necessity to power in the one-piece verse. these haki exists in different forms as there are various forms of haki, and one can develop them in various ways; for example, Katakuri who developed his observation Haki so much that he could look into the future, or Kaido who uses conqueror haki as an amour on his body for protection.
there are characters in naruto that can defeat Luffy but there are still characters in one piece that can beat naruto.
I heard this misconception on quora. someone asked could naruto beat all the Emperor of the sea at once? and everyone answered yes....like.....wtf. how can naruto take on all the four emperors what happens if one of them lands a single hit? I doubt that match will continue. there's a different aspect as to how strength is revealed in these animes. the naruto verse makes it seem like it is that easy to destroy a planet. maybe...yes/no I don't fully know but what I'm sure of is that the planetary power of naruto characters is based on their chakra, which can probably destroy planets. I'd like to see any character in naruto destroy even a city without chakraš¤§, they don't have as many physical capabilities as the one-piece characters and so far we don't know if any Naruto character can withstand conquerors haki. so next time you're grading power levels make sure to consider possibilities and not make it so one-sided.