Zoro has not been relevant to the plot since Post ts. I'm not baiting or slandering him, but Wano was the last wake up call we needed. Law is pretty much the deuteragonist since PH. The entire Dressrosa saga revolved around him. We thought it's ending for Kid and Law post wano but their story relevance actually increases. I think at this point Oda will carry them till EoS.
What does not being relevant mean exactly here? PH and Dressrossa deeply involve Law due to obvious reasons. PH is definitely Law's arc but it was the SHs that resolved Dressrossa for Law. Law's basically Dressrossa's Dolton or Wyper while Zoro and Luffy stood at the frontlines to save the country. Luffy's decision to save Dressrossa has nothing to do with Law actually. We give him credit anyways because he took them to Dressrossa and pretend Law's the one pulling the strings when it's actually Luffy who's making moves. This obviously deeply involves Zoro because he took out the second-biggest player at Dressrossa.
Law practically disappeared after Dressrossa and only became relevant in Wano. Even during Rooftop, he was treated like a background character. His true relevance only kicked in when Big Mom's fight was initiated, and it was a massive shared feat b/w him and Kid. Law is obviously very important but we're crossing the line when we pretend he's been the one controlling the narrative when it's actually the SHs. We've been giving him way too much credit just for being involved.
I can understand Law, but Kid practically didn't exist before Wano, and he's suddenly more relevant than Zoro because he took down Big Mom, who herself isn't that relevant in the grand scheme of things. Every single thing Luffy did in the past involved Zoro. And everything he'll do in the future will also involve Zoro. The plot revolves around SHs, not Luffy's rivals. They just exist to help create favorable scenarios for the main characters.