I just don't think things have to be one extreme or the other. Only Sith deal in absolutes, after all. Bird may very well want to move back to Sydney if the opportunity arose, but he may also be fine to stay for another year with the goal of playing good footy to make sure he gets to go back home in 2022 with a good deal. Kevvie may see the opportunity to free up some cash by cutting a deal, but also may not be so desperate to offload Bird that he doesn't mind if the right offer doesn't eventuate and can see a role for him in the 2021 team.
I've not seen or heard anything to lead me to believe Bird is a toxic personality in this team. Maybe he is - like just about everyone esle here I have zero inside knowledge. But the fact that he's now worked his way back from three season ending injuries shows he has some got some pretty rock solid fortitude, and that's is a trait I'd like to see rub off on the current team, honestly. And if Kevvie gets them playing good, fun, enjoyable footy, and they start winning more than they lose, I can't imagine Bird kicking stones and white-anting in the background.