Ace vs Marco confirmed.
If Kaido has yet to be referenced as the Ace and the Number doesnt exist (not as a 1 or something), i feel like it still should exist.
Better yet, if Luffy's brother was intended to be the Ace just purely from his name and not power, that would be odd considering 4 years have passed since he was even at Wano. In 4 years Kaido couldn't have found a replacement. Or how about 20 years since the other positions existed during Odens flashback.
Whats even weirder is in the volume, you can clearly still see 4 silhouettes for the All-Stars in Chapter 920/921 (forget which chapter).