I believe one reason you don't often see stories where a man helps an evil female character find her way back or a woman who is in a deep dark place, whether it's the "I can fix him/her" trope or a gender-reversed "Beauty and the Beast," is that some people see those dynamics as inherently disempowering or controlling when the person offering compassion just so happens to be male.
I'm not saying every woman views a villainous female character as empowering, but I do think that perception exists in some parts of many fandoms.
I don't think it's "misogynistic" or "controlling" or "oppressive" for a male character to get through to a female character who only wants to destroy/rule the world (just an example) because she snapped from her trauma and he believes she can helped upon learning about said trauma. That sounds like he simply has compassion for another person. If he's trying to understand her and help her change, this isn't about "controlling" her. Again, it simply is an act of compassion.
And for all of this talk about the importance of, "it's never too late to be a good person," narratives in fiction, many who support said narratives are quick to judge if it becomes romantic down the line for a hero and villainess.
In fiction, you do see a female character help a troubled or evil male character start down a better path. Her compassion is seen as a reflection of her strength, while it's still ultimately his choice to change. I think that same idea can work just as well with the genders reversed.
There's also something DEEPLY ironic about this reaction. It's often said that male audiences don't view female characters through a nuanced or compassionate lens. Yet, when a story does portray a man looking beyond a villainess' actions and seeing someone worth understanding and maybe even redeeming, and some men either like it or the idea as a whole in general, that dynamic is often met with skepticism or outright hostility.
At the end of the day, I don't see why men shouldn't be allowed to enjoy that kind of redemption fantasy too. They're allowed to like it as much women do, as they have their own "fantasies" as well.