It's kind of bizarre to read these past few pages of discussion about what potential role Yamato could be, and in the same breath imply that something would need to be kinda hammered home to the readers through dialogue or long standing desire to fulfill a particular role on the rest of the journey, when a. the proof is in the pudding just by Yamato's hopeful and naive demeanor particularly when she's not fighting, and the fact that Wano's flashback was probably the first since Brooks and Franky's to explore a new Pirate role on a ship through various characters we've known about for years but got an introspect on how they were when they were still growing as Pirates underneath seasoned veterans like Roger, Rayleigh and Whitebeard.
Nevermind the fact that before this Oda made a point to have Sengoku highlight that Kaido himself was the Apprentice of Rocks despite being one of the big names in that crew along with Newgate, LinLin and Shiki, when in reality it wasn't needed we already knew he was apart of the crew was enough implication that the three oldest Yonko share history.
Then here comes Yamato who fights like her Dad, who is obsessed with how Oden lived, who also was a Pirate noob before getting promoted to 2nd division commander, factor into this that Yamato has literal minimal life experiences outside of Wano if any at all and I think it's pretty blatantly obvious what their role will be.
She's not meant to be same old Pirate apprentice, Luffy has rarely recruited the standard version of the quintessential cremates. Zoro is a First Mate, but more so the muscle of the crew, Nami is the Navigator but bosses everyone around like a Quartermaster/second mate, Ussop is the brave but cowardly sniper who uses slingshots instead of guns, Chopper is a Doctor who's an animal and monstrous when need be, Robin is a historian/Archeologist who just so happens to be an assassin and clandestine operative, Franky is not just a foreman or carpenter but also a scientist. Brook is a dead musician and now a Pop star. Sanji has become much more than a simple Chef Pirate in the last two arcs alone, royalty, now super soldier.
If the Strawhats were to get an Apprentice, they wouldn't be kids like Buggy and Shanks or hell even BB. It's all right there , more so than even Jinbe being Helmsmen was subtly hinted at during the escape from Impel Down.
Cant have it both ways , either he hints at a preordained role or they'll be an extra pair of fighting hands.