i think that it's a lot more ordinary than many people believe.
just like the islanders in WW2 who formed the cargo cults, you don't have to be that much more advanced to seem like aliens or gods to people.
and i think that these people who got called gods when they lived here, don't want us to be treating them like gods either.
revelation 22:
8 I, John, am the one who heard and saw these things. When I heard and saw them, I fell down to worship at the feet of the angel who had shown them to me.
9 Then saith he unto me, See thou do it not: for I am thy fellowservant, and of thy brethren the prophets, and of them which keep the sayings of this book: worship God.
that's what i believe these people who "ascended to the heavens" are - just humans with greater knowledge who want to share what they know to help us, and yes, in exchange for having us around and maybe some of them will interbreed with us, to keep our genes intertwined and ensure that our relationship with them can continue. when it comes to genetics, diversity is definitely strength. 72000 years ago only 5000 humans survived. it doesn't take that many people to maintain the gene lines but without those options up our sleeves, as a species, we can become unviable, and that's what they continue to maintain a connection with us for.
we have rich genetic material in us that they have mostly lost, almost to the point where they are no longer human anymore, and they don't want to lose that. that's the main motivation on their side.
and while i do have some small belief in the idea of there being a spirit to planets and stars and such, i don't think that we are bound to it any more than we are bound to this universe as a whole.
it's important to understand that when it says in genesis that it was a crime that the fallen angels "took human wives" that's not quite exactly what was meant by it. they seduced, raped, and impregnated them, and then enslaved them. that was the great sin that condemned them. not the simple act of interbreeding. the violence. the exploitation.