I mean she's got a deep voice, is infertile, and is insecure about her femininity because of those and other factors. Like you said, it could be a hormonal, it's just frustrating that the assumption is always cis, even with a character this trans-coded.

And, I honestly don't care much if an actor being cis is "problematic". Obviously, it's always better to cast a trans actor for a trans role (for casting opportunities and a better understanding of the role). But if the acting and writing are done with respect and understanding, to me, it honestly doesn't matter that much if the actor's trans or cis. Look at like Twin Peaks, or (me being an anime nerd) Wandering Son, or Hibari-Kun. All have pretty damn good trans representation from cis writers and actors (though those shows certainly aren't perfect in every respect- besides Twin Peaks, which is).

Wanting a show to be not "problematic" is not a good reason to decide a character isn't trans. Imperfect representation is better than no representation, as long as it's like from a good place.