She needs to be put in solitary.
She identifies as a woman and looks like a woman so this does put her at risk from male inmates.
However, she has not completed her transformation and still has a penis so it isn't appropriate for her to go to a female prison either. Particularly as she is in prison for a violent assault - she might have the strength/stature of a man or at least her physical capabilities are disproportionate to other female inmates.
Solitary in either prison will protect her and others - she has been violent which is why she's in there in the first place.