So I'm kind of odd in that I'm quite unabashed about nudity in single sex spaces in that I will (quickly and not intentionally to show anyone, just out of practicality) get completely naked when changing in single sex spaces.
I don't believe there should be any shame in my body being naked for practical reasons in the presence of other women and girls. Quite the opposite. I think it's actually important for girls to briefly see how real women's bodies look when naked so as their begin to change they have some context for what's normal, instead of just what they are forced to see in movies and porn. I would make the same argument for boys. I know I was a bit embarassed to see it in locker rooms as a kid, but that became useful to me later. As my body changed and I felt intensely uncomfortable, I thought back to what I'd seen and I realized that my body was completely normal.
Including trans women in men's facilities, or trans men in men's facilities, OR this sort of unisex changing village actually has two costs. The first, more obvious one, is that some women will be absolutely excluded, as they cannot be seen in any state of undress by members of the opposite sex. The second, is that girls will no longer see the normal range of adult human female bodies as part of their normal lives unless they happen to be nudists. Alternatively they will be gaslighted as TRAs believe they should be into thinking that "having a penis" is part of the "normal range of adult human female bodies".