Team Darth MaulvsTeam She-Hulk

Team She-Hulk Jean becomes the Phoenix to solo. You cannot separate the 2, unless you go back to the days of Marvel Girl. That's not the version used here. But, it's who she will become when a battle is against her team. You'd have to be more powerful than the phoenix or be able to nullify/counteract Jean in a way that stops her from transforming. I don't see that happening, since The phoenix is "like" a split personality and symbiote*(a part of her).

*You don't need to have the weaknesses that the Spider-man's symbiotes have nor be as limited in powers in order to be a symbiote. A symbiote simply a parasitic being and the phoenix holds this sort of relationship with Jean.