Vanderhoven.... First, writing a book has always been an ambition of mine but life had always gotten in the way, so good on you for accomplishing that. My earlier comment was prefaced by saying, "Jewish notions of death were hardly uniform", and perhaps I should have expanded upon that.
Yes what we seem to know about the Sadducee movement was a denial of a meaningful afterlife (or resurrection), while apparently still accepting the idea of shades existing in Sheol/Hades. That's quite natural as they did not recognize works like Daniel and Enoch.
The Pharisee movement seemed to be more in line with the larger Jewish world in accepting the intertestamental doctrine of resurrection. The Essenes likewise believed in immortal soul that would be rewarded.
The Gospels depict Jesus as pretty much quoting works of this late period, like Enoch and Daniel, in comments about the resurrection, in his rich man parable as well as his Gehenna warning. Jude directly quotes Enoch. Revelation carries this same concept quite clearly. A straightforward reading of the NT leads to the conclusion that Christians had fully embraced the concept of an afterlife reward or punishment in darkness and fire. The immediacy of that outcome seems to have varied in specifics, but the overall concept was pretty consistent.
In this more progressive age this doctrine has become a bit of an albatross and as a result it's become more popular to argue for it not being a Biblical idea. To do that usually they draw from OT texts written by earlier writers before the doctrine of resurrection was (possibly) adopted from the Zoroastrians, as if this proves later Jews did not believe it.
Next, they have to dismiss passages in the NT that clearly express this thought, usually by labeling them as metaphor or symbolism, or in the case of the rich man parable, declare since it was a parable it wasn't a reflection of beliefs. As if that somehow makes sense.
I respect anyone who rejects the concept as barbaric and vengeful but am perplexed by those who dismiss the doctrine while clinging to the writings that teach it.