That's pretty damn hypothetical, especially because Valentina always looks phenomenal, no matter who's she's facing. Amanda Nunes, Joanna, doesn't matter. Of course we'd never see her perform against a man, at least in any professional sense. Of course Valentina doesn't beat Barboza because of obvious physical differences.
How do you think Barboza would look trying to perform a spinning kick against Cro Cop?
You gotta look at in relative to their own weight class, and when guys like Wonderboy say Valentina has some of the best moves in MMA man or woman, I tend to take that as a pretty good indicator.