One Piece Last Volume = First Volume
Chapter 1192 ---> Romance Dawn/Dusk ---> End of Final War Events
Chapter 1193 ---> Zoro + His New Epithet ---> Chapter about Zoro & Mihawk
Chapter 1194 ---> Luffy + His New Epithet ---> Chapter about Luffy & Shanks
Chapter 1195 ---> Main Villain of Story ---> Chapter about End of Final Villain or his Fate Post-War
Chapter 1196 ---> Pirate King & Greatest Swordsman ---> Chapter about Luffy/Zoro finally achieving their Dreams
Chapter 1197 ---> The Last ---> End of Straw Hats Pirates & Final Farewell
Chapter 1198 ---> Nakama or a Related Name ---> TimeSkip happens & we see how all Straw Hats are doing Post-Adventure
Chapter 1199 ---> Nami or Title related to World ---> Updates on all Locations/People we've seen & World Map at the End
Chapter 1200 ---> One Piece ---> Chapter about Luffy & his Legacy + True meaning of One Piece & Luffy/Roger's True Dream
I'm 99% certain about this Last Volume.
As for Previous Two Volumes, they will be about other Seven Straw Hats, all achieving their Dreams & Conclusion of their Stories, 3 Chapters for each Straw Hat, resulting in 21 Chapters, which is Two Volumes. While Last Volume is for Luffy, Zoro & Nami.