One of my favourite series of all time is Jean Auel's Earths Children series, about cavepeople. From the third book on, the protagonist lives in matriarchal, communist societies, free love, everything shared, people can be gay, in throuples, whatever they want. But at the end they discover where babies come from, and the society turns patriarchal and it ends with women clearly about to lose their freedom.

I really enjoyed Forty Millenniums of Cultivation

It's a (3000 chapter!) sci/fi cultivation fic written by a Chinese communist who drinks their respect women juice.

It discusses a lot of concepts in really interesting ways, has good and believable character development, and has a beautiful, hopeful, message, and regular scenery tearing xianxia mecha space battles with the fate of the universe at stake.

I already recc'd The Years of Apocalypse to you the other day but I'll put it here again for anybody else reading the thread.

Sunspot is great, lots of gender happening in there.

Noctoseismology and What Little Remains of Terpsichore Ironheart are both good but also very horny trans-centered stories.

been recommending this one a lot

This is an outside pick but I really like the paradox megacampaign Blood in the Bosphorous. There's a ton of it https://forums.somethingawful.com/showthread.php?threadid=3603375&userid=0&perpage=40&pagenumber=1

I thought of another one! I'm convinced this can be read with zero familiarity with caves of qud or touhou, but I have yet to test this hypothesis https://archiveofourown.org/series/2131317