https://youtu.be/_HdIGu5T7l0Genesis very briefly glosses over what the book of Enoch went into much greater detail on.
That some angels rebelled and came to Earth, to teach humans, and also mated with them.
Genesis:
>Then the Lord God said, “Behold, the man has become like one of Us, knowing good and evil; and now, he might reach out with his hand, and take fruit also from the tree of life, and eat, and live forever”God was so upset with the problem of humans _knowing_ things, and the angel/human hybrids, he saw fit to flood the world to erase it.
It's overwhelming evidence that GOD DOESN'T WANT YOU TO KNOW things. He doesn't want you to KNOW what happens after death. He doesn't want you to KNOW he exists.
He wants to keep humans ignorant and guessing, and he has succeeded.