My position is Wano arc is 3 Acts.
Not having Kaido defeated during the Night of the Fire Festival and before the 'dawn' is anti-climatic.
The Alliance can't lose outright otherwise the people of Wano are f*cked and they won't be able to regroup and fight at this scale again as they'll be dead, imprisoned and overall too weak to fight back again.
For a plot point of view, it makes more sense to transition to the outside world events after Kaido is defeated and we can get the reaction of others as news spreads.