People need to stop coping with the "Jinbe 2.0" situation.
It just does not make sense for Yamato to just skip an arc or two for no reason and join later.
Think about it, Oda could have used any other reason for Yamato to stay, but seemlingly he made up a new one that does not even make sense. Why? Easy, all the other reasons were "permanent", but this new bullshit one lets Oda keep the possibility open for her to return "at some point" keeping at least some of the fanbase on hopium. But just like Yamato telling she'll join for two years, its not going to happen.
Honestly the best her fans can do is stop drinking the snake oil and let go. Just like every other character in the series she'll be back for 2 panels in the final war.