What is The Expanse?

To the choirmaster. A Psalm of David. The heavens declare the glory of God, and the expanse proclaims his handwork.

I recently ran across the ESVCE translation of Psalm 19, the beginning of which is above. I've taken the liberty of substituting the alternative translation of "the sky above," which the footnote says is equivalent in Hebrew to "the expanse", and invites comparison to Genesis 1:6-8 (sic):

⁶ And God said, “Let there be an expanse in the midst of the waters, and let it separate the waters from the waters.” ⁷ And God made the expanse and separated the waters that were under the expanse from the waters that were above the expanse. And it was so. ⁸ And God called the expanse Heaven. And there was evening and there was morning, the second day.

Well, that's blatant—no substitution by me here. The footnote says that expanse is equivalent to "canopy." Of course the heavenly canopy is reflected in the chuppah at a Jewish wedding.

I've seen a lot of people saying the title of the science fiction novels and TV series The Expanse has to do with mankind expanding out into space. But I haven't encountered anyone who made the connection to the ancient Hebrew Bible.

What does this connection say about the story of The Expanse? Is it some sort of covert Jewish or Christian story? Doubtful. While the story does highlight many real virtues in its heroes, it's not like they're unique to traditional Christianity or Judaism in the modern era. And being as the main hero has eight parents without the obvious psychological issues that would accompany such an artificial upbringing (at least in the TV series; I haven't read the books), the authors don't seem to be much in mind of any sort of Biblical or even natural morality.

Additionally the individual books of the series are titled with literary and historic allusions, e.g., Leviathan Wakes, Caliban’s War, Abbadon’s Gate. So The Expanse fits in with such allusive titles, and obviously the stories take place in "the expanse" of space.

But is there more to the allusion of the series title? For example, is the overall story about a wedding of sorts? What do you think?

Of course, there is Miller's pursuit of Julie, a romance of sorts perhaps. But that's resolved early in the series, no? Or perhaps it's synecdochical, similar to The Thin Man series with the epithet reflecting its first installment? Or is there a larger marriage the authors have in mind?