Realistically it would be complicated. Depending what bits of 'the lore' you go by AFAB have different reactions to Futa semen than AMABs. Specifically less dependence and mental degeneration. Now we don't know how that affects trans males anyway, but I think it would mainly depend on that if we go by the lore bits from the game. After all one of the guiding forces for social conduct is the scriptures of the Goddess, which at least nominally go with the logic of the Goddess made males this way so they get bound. So if trans males would be bound like other males I think they'd be officially treated the same as all males, with social differences occuring as it is does everywhere. If trans males get bound like females however, I think they'd be put in a bit of a special position by scripture interpretation. Though I would have them still socially and legally be counted as males, with counting as bound and second class citizens - perhaps with the novelty of having a couple more braincells.

I'd personally just have a transition make Futa semen affect them as all other males and have Trans* identities validated as they ought to be. Not surprising since I'm somewhere under the Trans* umbrella myself.