Maternity does not matter. The crown passes paternally. That's why the Torah talks about the seed of David, not the egg of a woman. The promise was tho Adam through Seth, to Noah, to Shem, to Abraham, to Isaac, to Jacob, to Judah, to Peretz, to David, to Solomon. The scepter was not promised to the line of Nathan. Mary cannot pass what she does not possess.
Talmudim always go back and forth, don't they? They describe Judaism and Deuteronomy 7:3-5 as the writers of Kiddushin interpreted Torah; then they try to invalidate what is actually valid matrilineal Judaism and status as a melekh-Yisra'el. Miryam bat-Eli was descended from Eli, who was descended patrilineally from Natan ben-David. We don't know about the matrilineal side unless the various challahim are identified by name; so Miryam could also be a matrilineal descendant of Shlomo ben-David.
Yeah. But, I don't think she was a man. The scepter cannot pass from her. She cannot pass what she does not possess.