Yamato hate his/her father kaido
Yamato want to explore outside island (not sure why he/she is chained too)
Yamato not evil like beast pirates
Yamato want to complete oden goal
With that motive, it doesn't fit to be luffy straw hat crew.. Can't imagine her/his role in the ship.. Too many second char strongman to be highlight-ed (zoro sanji jinbe) as well.. Will make oda hard to manage screen time..
I think later yamato of wano / 2nd gen of beast pirates will be more like Grand fleet Alliance (Cavendish & bartolomeo pirates)..or be more like allied Teritorries / fellow pirates like fishman, minks, samurai, law, bege, katakuri 2nd gen of sweet pirates, sabo 2nd gen of revolution army. . In final stage VS world government..