I can see the similar relationship stuff, but why is that directly correlated to strength? I never thought the Zoro/Sanji rivalry/dynamic was really about strength, I always felt it was how their personalities clashed with each other. Particularly with Queen/Mr.2 compared to King/Mr.1, it's the eccentric and quirky dude clashing with the no-nonsense, serious dude. But it's not like any of these characters (Zoro and Sanji included) ever really challenged each other on the basis of trying to prove they are stronger, but more that they just get easily pissed off at each other
I'm not saying there's a massive gap between Zoro and Sanji, but it seems like ONLY when it refers to them and their opponentswill people try to downplay the gap so much that they treat it as something negligible