The traditional Christian understanding of the Bible, that goes back to Jesus and even to Moses, is that the Bible gives the true version of the stories that also ended up in the lore of other cultures. It's not that the others are original, they are simply what was picked up by people in various distorted versions from their ancestors on the ark, but since God inspired the Bible we get the true story there. Unbelievers generally prefer the fictional account of course.
Well that is an awkward view, given that the Hebrew version was written well AFTER the other ancient versions.
Well, again, it IS the traditional understanding of believers.
And Abraham goes back to 1900 BC, which is more than a century before the date imputed to the Epic of Gilgamesh even by the scholars whose dating acumen you would of course trust over the Bible's. I'm not sure if Noah was still living in Abraham's time but his son Shem was. Of course Abraham didn't write it down, it was verbally transmitted down to Moses who wrote it.
Amazing what you think you can know without any source of information except your own feverish brain, and even think you can contradict the source of information we DO have. Modern man's self-confidence is really quite remarkable. Evolution gone wrong perhaps?