sking all Creationists, theologians, and general biblical tradition experts of Reddit: What is the antediluvian world believed to have been like?

I am in the brainstorming phase of a science fantasy short story, and part of it involves traveling to the antediluvian world.

I am aware of the general information that the people of this world were “wicked” (the reason they were flooded). I am also aware of the existence of the Watchers (angels who were tasked with watching over humanity), who in turn mated with human woman and created the Nephilim (giants). I’ve also heard the myths that the Nephilim were blood thirsty and threatened all life on Earth.

I’ve also read a little of the Books of Eden (Adam and Eve), which talk about the descendants of Seth (also called the ‘Sethites’, they were descended from Adam and Eve’s third son) living atop a mountain and the majority being slowly tempted down by the Cainites (descendants of the fratricidal Cain).

If some could expand on some of this information, it would be appreciated: But what I’m really interested in learning is what the actual conditions of the world were like in this time. Much thanks in advance.

Note: This is not a theological debate or a discussion about creationism/evolution. I personally don’t take the Bible as literal fact in all facets, but I am respectful of another’s beliefs. Please keep any discussions respectful and do not stray into any debate.