I'm sorry, but now I'm confused. White Knight does have a gender undertone, at least in gender discussions. It wouldn't make sense to apply it to women, since the goal is painting the person as the stereotypical knight in shiny armor that comes to save the damsel in distress.
I'm sorry but in my world a White Knight is an amorphous (and obviously genderless) entity that bears any kind of armor (not just the shiny ones!) and saves other amorphous entities in distress.
Please consider revising your definition so that you stop excluding people with your close-minded 'cis' stereotypes.