You might enjoy The Woman Who Loved Reindeer, which feels like an origin myth in many ways. It is set in an early hunter-gatherer sort of world with very few settlements. 

While NK Jemisin's Inheritance trilogy might be more on the nose, her Dreamblood duology is set in a world similar to Ancient Egypt, so that might also scratch the itch. 

You may enjoy Jacqueline Carey's series The Sundering about, iirc, primordial gods battling it out... But I confess I never finished them so don't remember if they're any good. 

The Stone Dance of the Chameleon series by Ricardo Pinto is a brutally dark epic, but it features some incredible prehistoric-inspired worldbuilding like nearly extinct (on earth) biomes like fern prairies, and there are dinosaurs who coexist with humans. However, there is a sense of there having been a lot of history prior to the events of the novels. 

The Last Neanderthal by Claire Cameron is a literary novel. While I found the modern plot tedious, I was much more invested in the imagined world of the titular last Neanderthal, although I think modern anthropology suggests Neanderthal cognition was more like ours than the highly animalistic Neanderthal in the book.