When I was a teenager, I went to church, and almost every ‘Christian’ there was a complete asshole. What makes it worse is that they try to justify it. This honestly made me think that if God and Satan were real, I’d want to know Lucifer’s story. Maybe he’s not actually ‘evil.’
I agree in general but I can't think of anything in the OT that is taken from The Epic of Gilgamesh except the Noah's Ark story, which is a clear rip-off. And the 5000 years ago is too long, I think the oldest books are from the 8th century BCE.