Reading One Piece long enough, long arcs tend to have a sort of structure in their volume covers. Looking at Dressrosa, Whole Cake Island, and Enies Lobby, there’s this thing that becomes obvious.
And then Post Credits/Post Arc. If my hypothesis is correct and Volume 98 is the “allies” cover, then Volume 99 should be a volume where we see “The Villains”, showing off the Beasts Pirates Commanders (Lead Perfoemers and Tobiroppo), Kaido, and maybe Big Mom.
Volume 100 should be a milestone volume, appropriately featuring “The Heroes”, or all the Straw Hats. It should also feature the defeat of rest of the Tobiroppo and Lead Performers, and also Perospero. Luffy vs Kaido should heat up at this point.
Volume 101 – This will probably showcase Luffy vs Kaido a la the Katakuri, Doflamingo, and Lucci covers. The plot will probably have whatever ticking time bomb Wano needs already active to occupy the other Straw Hats.
Volume 102 – Whatever this volume is is gonna be pretty wild as Kaido and Big Mom should fall and the news reported. Bounties here, there, everywhere.
This also clocks with Wano ending this year and us seeing Vivi, Sabo, and Shanks.
*Theory by GabrielMichaelson