I think Luffy might be able to extreme diff Dragon!Kaido if his stamina holds up, but:
- Luffy hasn't dealt much damage to Kaido with any of his attacks either.
- Boro Breath still hurt Luffy visibly despite him tanking it.
- Boro Breath seems to have dealt more damage than Kong Rifle.
Luffy vs Dragon!Kaido comes to a battle of attrition and I don't like Luffy's chances there because of stamina issues.
Zoro shuts down Dragon!Kaido's entire offensive arsenal, and can bring him down quickly using his Upper Tier techniques. Dragon!Kaido literally has no hope of beating Zoro.
Kong Gatling should disorient Dragon!Kaido enough for Zoro to land Hiryuu Kaen or any of his other Upper Tier techniques. It's all downhill for Dragon!Kaido from there.