Greetings,
Clearly, if the angels or sons of God can mate and reproduce with human women, they cannot be too far from homo sapiens.
The texts indicate that God was just another member of the Elohim:
1 <A Psalm of Asaph.> God standeth in the congregation of the mighty; he judgeth among the gods.
6 I have said, Ye are gods; and all of you are children of the Most High.
7 But ye shall die like men, and fall like one of the princes.
(Psa 82:1,6–7 KJV)
Above we have God speaking to the council of the gods. Or we might say that we have the leader of the Elohim speaking before the council of Elohim.
6 Now there was a day when the sons of God came to present themselves before the LORD, and Satan came also among them. (Job 1:6 KJV)
Above in Job, we have the same sort of council meeting. The sons of God equate to the Elohim of the council equate to angels. Lord God is the ranking angel of the council.
If Lord God is simply the ranking angel, and if angels can mate with human women and produce viable offspring, then God is not very far from humans.
These angels or sons of God are possibly an earlier derivation of Homo Erectus that had reached an advanced form of scientific knowledge and undergone genetic modifications for longevity. Lord God was the title of the leader of this particular group of proto-humans that were engaged in a long-term project to methodically civilize the newest breed of wild humans.
This 'angelic' species might have been from something like Denisovan or Neanderthal stock that had passed through a few thousand years of civilization in a society now lost beneath the seas.
They were close enough genetically to allow for interbreeding with the wild homo sapien species. Their genetic modifications were passed down to their offspring resulting in lifespans of around 900 years among Adam and his descendants. Such a modification isn't likely to die out on its own as it allows one to have more children than others and these children will also possess the genetic life extension modification.
When a company of 200 Watchers rebelled and took wives from the daughters of men, the number of Nephilim increased exponentially, and the genetic modification threatened to race through the entire population.
That's why God decided to limit the lifespan of humans, at least within the context of the narrative.
God may have banned man from eating from the tree of life, but there was nothing done to prevent other sons of God from mating with human women.
Lamech had ample reason to suspect that a Watcher had fathered his 'son' Noah with his wife.
Paul also wrote of the danger of angels:
9 Neither was the man created for the woman, but the woman for the man.
10 For this cause ought the woman to have power on her head because of the angels.
(1Co 11:9–10 KJV)
Women need to keep their heads covered and protected with a magical seal so as not to attract the attention of angels because women were created for men and not for angels.
The author of Jude also clearly drew from the Book of Enoch, demonstrating that at least some of the New Testament authors were familiar with the Book of Enoch and the stories of angels taking wives from among the daughters of man. And they knew that the resulting children would be extraordinary.
The template was laid down in Genesis, so when an angel appears and a woman later miraculously gives birth, it really isn't all that miraculous. Even, or especially, if the surface reading argues otherwise.
At the same time, I have never denied that syncretism was a significant factor in the creation of many Christian texts and the theology of the Church.
My point is that angels mating with humans and producing hybrid beings is the stone on which the Church was built, and it dates back to the formation of Genesis.