Depends, it can entirely end well in a chapter if paced well, drawn well, and all 3 characters are given good moments and final attacks. You only need a chapter to do this.
Most fight in one piece do not last longer than 1-2 chapters outside of Luffy's. Plus, Big Mom HAS been fighting since like 985. Look at these panels (warning long post and I'm not putting it in spoilers unless mods force it):
This is discounting any of the awakening scenes or this chapter. Big Mom has done ALOT this arc. And where you don't see Kid/Law directly fighting her, they were fighting Kaido beforehand in other huge double spreads.
Seriously if Wano is remembered for anything, it needs to be for its action art, because this is the most Oda has drawn action in any arc ever, by a stupid huge margin.