In any case the one that say First Yonco Comander are trash, are rely delusional, first we have the gorosei saying that after White Beard died, Marco was potentially the next Yonko in line (which clashed vs King for over 20 chapters in Onigashima).
Second we had Katakuri which was even more efficient and lethal than Big Mom in her arc in Cake Island, which put him as a potential candidate as Yonko.
Now we have King in which White Beard said that his race :
Shirohige: "Long time ago, before the time of Mary Geoise,
there was a "country of god" above the Red Line.
His statue is regard as a God, let see what that mean.
In any case, I dont even see Kaido having an easy win vs King, all chatacter have to put some work to take down a 1Yonko commander.