So basically rookie Ace = Yamato?
We also know for a fact that rookie Ace = Jimbe
We then have Yamato = Jimbe, and we know that Jimbe is going to fight Who's Who in this arc, so we can safely say that Jimbe is around Who's Who level
Who's Who is below calamity level, so the bottom line is: Calamity > Who's Who = Jimbe = Yamato
So Kaido's offspring is just a fodder after all lol