Reading this as an outsider, it’s imperative that you separate your relationship with STBXH and your relationship with DD.
Your STBXH hasn’t covered himself in glory, although I tend to be more sympathetic to his situation than some. As long as your DD isn’t exposed to his porn then it’s entirely irrelevant to her. As long as your DD hasn’t been used by him to facilitate his extramarital sexual activity then it’s entirely irrelevant to her. She is etitled to her own view on trans in general and on his trans status specifically, just as you are.
From DD’s perspective, STBXH has been her primary carer (you said in your OP that you have been the breadwinner), he doesn’t slap her, and he has her trust. I think it’s unfair, based on the information given so far, to accuse him of being a Disney Dad - quite the opposite, actually. We don’t know what any of the rows between DD and OP have been about, so can’t say if STBXH is too lax or OP is too harsh.
Your best bet, I think, is to do exactly what you’re doing - move out, take the heat and pressure off all of you, focus on getting your finances and contact arrangements agreed, and the divorce finalised ASAP. Only then can you move on for yourself and for your relationship with DD.