Kaido and Big Mom will fall at the same time. It won’t be one before or after another
But it's Oda, so don't hold your breath, the guy starts having withdrawal symptoms when Luffy isn't being singled out on panel. And this is the biggest moment in Luffy's pirate career, by far.
Oda hasn't budged for over 2 decades, hard to believe he does it now when it matters most (even though the evidence is piling up). The most he does is give minor Ws to side characters before he sends them off to witness and bathe in Luffy's greatness. Defeating Big Mom is far from that.
He would probably be hospitalized if he drew that, coughing up blood and shit, maybe he pulls it off but he's gonna need a lot of willpower. Just imagine a die hard Luffy fan on this forum drawing One Piece, that's more or less Oda, think of it like this and you'll never deal in absolutes.