Again from the begin:
So far Kaido make two statements, so he is the source of the current debate.
Kaido face Kid and Killer and easily beat them, guys around the same lvl like Luffy and Law, who defeat Doflamingo.
In case he sees Doffy under the lvl of Kid+Killer. In case when he face both Sulongs, he hype them as very strong.
I case of Kaido own experince and viewing the opponents who face him.
Sulong Dukes>DR Luffy/DR Law since he call them weak based on his experince when he stomp Kid and Killer.
Based on that perspective and portrayalwise:
Jack>DR Luffy/DR Law=Doffy
@Sadistic Senpai portrayal based on the manga panels and Kaido statement aren´t wrong.