It seems to me that genesis is a potted metaphor for human history.
All of it? It combines so many different styles and points of emphasis, that to regard it as a
singular metaphor is ludicrous. If you mean that you choose to regard Chapter 2 as such a metaphor, then that is your prerogative. As has been pointed out, the story has different implications in its earlier origins, and the Gnostics made a completely different metaphor out of it from the one you seem to prefer (which is presumably the Pauline one)
By what warrant do you seem to be equating wordage with importance?
In the Old Testament, it's a reasonable assumption to make. The matter is complicated, but does involve some of the ideas which have evolved concerning the Documentary Hypothesis. The earlier material of Genesis (the Jahwist (Chapter 2) and Elohist accounts were probably combined after the fall of the northern Kingdom of Israel after the Assyrian invasion. Then, in the court of Hezekiah, a scribe obsessed with what he considered to be divine laws, reacted to this earlier material and wrote his own account of the subjects dealt with. This scribe is known as the Priestly Author, and he wrote the account of Creation related in Genesis 1 (no anthropomorphic God, different sequence of events, and importantly - man and woman created in God's image, not woman 'taken from Adam's rib'). It seems this scribe would have liked to reject all the earlier J and E material and replace it with his own account.
Later, in post-exilic times a further redactor decided to reinstate the earlier material with some bewildering and contradictory results (the story of Noah is cobbled together from the two contradictory accounts, as is the 'Matter of Peor' in Numbers). This redactor may well have been Ezra, a speculation which even St Jerome thought highly plausible.
At any rate, though the laws and covenants related at length by the Priestly Author get referred to often by later prophets, the Adam and Eve story doesn't seem to have entered their minds at all. That must signify something.
Okay, as I said, Paul obviously thought Genesis 2 explained the nature of the world and humanity's place in to him, and made the story a major part of his theology. Bully for him. It doesn't resonate with me.
Jesus, in his one reference to creation "He made them male and female" sounds to me as though he was referring to the Priestly narrative of Genesis 1. He was of course taking a hard line on divorce when citing this - not one which liberal Christians may find very sympathetic. And not only Christians.