I like role reversal stories in historical fiction, however impractical and untrue they really are. Why should fiction try to be especially honest, practical or factual? If you can’t spin a few tall tales you may as well be writing non-fiction.
Dream up a character: a woman knight. She might be a secret knight, living among the men as one of them. Or, she could be accepted as one of them even though she is a woman. What is the story behind her? What does she look like? How did she learn her fighting skills? What does the future hold for her? Could she ever retire (before she gets killed off by another knight)?
My woman knight would be raised by dragons, never really knew her human family. She becomes a knight to fight for the dragon cause. She doesn’t wear skimpy stuff the way women are drawn and shown in film. She is a full knight, with a full suit of armour. No horse though. Horses would just be too scared of the dragons.