I'm starting to wonder if this "saga" even ends with Wano. Rocks plot bejng perpetuated into something bigger, im starting to believe Kaido/BM may survive the arc, reform the Rocks pirates, and we see an arc where all 4 Yonko collide over ancient weapons or something in God Valley. Idk, with the way Kaido speaks, it almost sounds like his plot can't be over just yet after Wano. He talks about stuff in the future (looking for ancient weapons, converting Wano into a lawless country, etc)
Weird to me if he himself goes down after this, but this is also me banking on an Ace existing and Luffy fighting that person instead.