I wonder if we could tease this out in a couple of ways (this is just an initial thought experiment). The first thought may or may not be relevant, since it brings in some connection between rebellion in the the divine realm and human rebellion. I know you take a non-divine view of the sons of God in Gen 6, but I assume you agree with the serpent in Gen 3 as more than a snake. Then we have Gen 10-11, which brings in what Heiser calls the “Deuteronomy 32 worldview.” An allusion to Babel (and subsequently the Table of Nations) is here (following DSS/LXX not MT): “When the Most High gave to the nations their inheritance, when he divided mankind, he fixed the borders of the peoples according to the number of the sons of God. But the LORD’s portion is his people, Jacob his allotted heritage” (Deut 32:8-9 ESV). Other relevant verses are Deut 4:19; 32:17; and Psalm 82. The overall point is that divine rebellion and human rebellion go hand-in-hand (and it’s universal). This does not take away human responsibility, but adds a “supernatural” angle often missed (which is also why the redemption of Christ includes a defeat of supernatural forces, including a reversal of Babel at Pentecost). Of course, it would take much more time to unpack.
Second, with or without the above, might there be an analogy between Noah (the second Adam) and Israel (also a second Adam). Noah was elected and rescued out of a universally sinful generation. Likewise, Israel, beginning with Abraham, is elected and rescued out of universally idolatrous humanity. However, Noah took his sinful nature with him on the boat, and so fell like Adam on the other side. Likewise, despite God’s grace to Israel, she too would fall because she is made of the same stock as all humanity.
This fits not only Heiser’s work, but much of what N.T. Wright has done. And it fits the idea of Adam being elected out of an early population. I guess the one difficulty here is that we are now pointing to Adam as the fountainhead of rebellion. Stlll thinking…