Doesn't matter what your opinion is though. Bias and fan wishes are what account for like most of the weekly disdain against the series.
Nothing implies Zoro is going back to the roof. There isn't one lick of dialogue or event that proves it at this time. Zoro hasn't said anything. Yamato has claimed Luffy will win. Momo and Luffy have claimed Luffy will win. Zoro himself claimed Luffy will win.
I'm not sure what else people need to to think realistically about this...
The fact that Zoro suggested to go back to the performance floor. The fact that Sanji is fighting Queen. The fact that nearly every major arc, Zoro always fights the Number 2 while Sanji fights the Number 3 (which is already half true this arc). The fact that back in Chapter 999, Marco himself mentions he intends to fight Kaido but will "help" the performance floor first (indicating his fight against King may not even be permanent).
Let alone the fact that King is a swordsman (he's used it to cut off Marco's wing), the fact that the recovery medicine he is on has a time limit and the fact that it's highly unlikely Oda has Zoro repeat the SAME exact journey to the roof to fight Kaido (i.e. Marco flying him up through the hole) anyway.
Story supporting fights is one thing (Sanji vs Queen) but not every fight needs to be thematically related by story. See Franky vs Sasaki, the setup to their fight wasn't even defined by the story. Same with Jinbe vs WsW UNTIL their fight was shown. Sanji vs Jabra had literally zero story connections. He got into that fight and finished it in 2 chapters.
Zoro vs King doesn't need any prior establishment. What IS established are clear patterns Oda takes in the story, and I suggest people look at it more often. Let alone the fact of what I just told people. If Oda is telling people, repeatedly, that Luffy is the one to defeat Kaido, it highly suggests Zoro has nothing to do with Kaido at this time. If that's the case, and he's recovering, he's best reserved for the most available fight in his location, which is King. Doesn't matter that Marco is fighting him, it doesn't mean he will be in 2 chapters, or 5, or 10.