I'm not claiming that ancient people were dumber, I'm claiming the cultural and spiritual purpose of a creation myth isn't served by realism or logical consistency. God creating day and night before creating the sun and moon is par for the course for these stories. The Babylonian myth some people believe Genesis is based on - the Enuma Elish, says the god Marduk killed his nemesis Tiamat, cut him in half and made the sky out of one half and the Earth out of the other.

>alternatively, if in the past they were using dream logic (which you also seem to belive ought to be expediently discarded) couldn't they also dream about other varieties of days?

I don't know why you're being so defensive, or why it's so important to you that Genesis be justified rationally. If you want to believe the ancient Hebrews based the days of creation on galactic rotations, go right ahead. It would just be odd, given that no one back then knew what stars, planets and galaxies even were. The timeline still wouldn't make any sense

And sure, they could probably dream of other varieties of days, whatever that means, but again - why have a narrative about six days refer to that rather than just six days? And why did they never write this dream down, or mention it? Surely they would have considered that a divine revelation from God.

The story says days, it means days. Regular human Earth days. There's no reason to believe otherwise.