The point about ZKK is also about the consequences of this. Lets reflect about it: the killing of soneone like Kaido,would make that person a legend. Zoro would obscure Luffy's fame in the One Piece world! And for obvious reasons this cant happen. Even if Luffy defeats him,people in the OP world will remember the one who actually killed Kaido,but Luffy is the man of the legends,not Zoro or any other Shs. They will be remembered too but not in a way that steals the spotlight from Luffy.
Exactly, Kaido's death is simply too big of an event for Zoro to be the one to take the credit for it, it would put him on another level in the eyes of the WG.
Kaido's status and political influence as a yonko takes precedence of him being a dragon or Oden's killer.
We have so many characters other than Zoro who have just as much narrative reason to want to kill Kaido but no one will entertain the possibility of it happening, because that's not how the story goes.
But Zoro fans have convinced themselves that Zoro is already a god and ZKK is basically another way of pushing that agenda further.
After all, if Zoro kills Kaido, and Mihawk is Zoro's objective, that means Mihawk is above all the yonkos clearly.
Like seriously how do people expect Zoro to kill Kaido and still have future antagonists that are being clearly set up for him like Shiryu to be threatening when he can already defeat the WSC and surpass his captain while at it.