The 5th One Piece movie, 𝘛𝘩𝘦 𝘊𝘶𝘳𝘴𝘦𝘥 𝘏𝘰𝘭𝘺 𝘚𝘸𝘰𝘳𝘥, while non-canon, explored similar story beats that WCI would show years later. Zoro goes off on his own, and Luffy sets out to find him. For reasons unclear to the crew, Zoro is acting strangely when they encounter him again due to his past. He ends up fighting Sanji and injures him badly enough that Sanji ends up wearing a sling. The villain, Saga, tells Luffy that Zoro will no longer be part of the crew. But Luffy never loses faith in his return. In separate moments, Luffy and Zoro both told the enemy not to underestimate the other after being told the other had lost to Saga. They ultimately defeat Saga together, with Zoro landing the final blow.
I think this movie captured how Zoro would handle a WCI-like situation. He would do his own thing but never reject Luffy's help.
BTW, the movie is refreshing. I remember watching it the first time and thinking it was a bit ridiculous, but post-Wano, it ages surprisingly well in its concepts.