Few ways this can go.
-Oda does not grant Kaido's wish of death. He's a bad guy, after all, why should bad guys get what they want. He is instead wrapped up in Seastone and thrown in Udon as karmic justice for what he did to Wano over the years. This also has the bonus that if Oda needs to use him again after Wano, he can.
-the especially cruel option. He gets his death, but it is an ignominious one. He doesn't get to die gloriously in battle. This would be something like being backstabbed by Big Mom- fitting for all his talk of pirate betrayals- or the resurgent Orochi- what goes around, comes around. Even something like Kine'mon cutting his throat as he lies defeated after battle, but that would be a massive tonal change from Oda
-gets his wish, glorious death. As for ZKK- I see the argument, it has merit, but I can't quite bring myself to argue for it. I cannot see Zoro overshadowing Luffy to such an extent where he's the one who actually kills Kaido. I fully believe that Zoro will wound him, but killing him is a bit too far. I think, if Oda were to go this route, it'll be more like Whitebeard's death, where the accumulated damage he's suffered leads him to sort of die on his feet. Luffy learning internal Haki destruction is very important for this route, because it would answer the question as to why Luffy suddenly killed someone after over a thousand chapters of the opposite. It'll be the destruction caused to Kaido's innards (plus all the other damage) that sees him off.
There's a few other options, like Kaido escaping or Kaido somehow getting a last minute redemption and holding off Blackbeard or someone like that, who actually kills him, but I'd find them to be very unlikely.
I think Oda will go for the third option, where Luffy lands the last punch, collapses, everyone's down, looks like Kaido's won but he's actually died on his feet. That would be the most "epic" way of ending it, and I think that would appeal to Oda the most. Having said that, I could very easily see option two.