Is there any evidence of this?

If you look at our closest primate relatives, they seem to demonstrate the opposite of what you are saying. I’m pretty sure there are far more “incel” chimps than bonobos.

I would assume this is not true. In a female dominated culture, women are much more sexually promiscuous. If they are allowed to be much more sexually promiscuous, they will also be less picky.

Maybe I’m too influenced by the fact that I know I won’t be having just anyone’s baby. But the more I reject “slut shame,” the more willing I am to slum it for the sake of convenience and efficiency.

Also, no matter what, humans are relatively wired to be somewhat monogamous, as indicated by minimal sex differentiation. Nuclear families allow for better long term parental investment in offspring. So there should always be limits to what level of polygamy is ideal. This is true even for men, whose offspring fare worse worse when the father is absent.

Also, no matter what, both genders have biological incentive to produce genetically diverse offspring. So multiple reproductive partners over a lifetime is ideal.