the idea of the immortal soul comes from greek philosophy and isn’t biblical at all

Sorta. You have the Nephelium which are strongly hinted at to be the ghosts of great warriors that died. You also have the Witch of Endor who can channel ghosts. Their idea of an immortal soul wasn’t consistent and it is reflected in the Hebrew Bible. You are right however the Christian concept of the soul most likely comes from Plato.

I don’t know why you say hell isn’t a place. The word comes from a physical location that you can even visit if you want in Israel. As for Luke he was clearly just copying what Paul said about “if they knew what they were doing…”. Because Paul had to explain the nonsense story related to him.