Why can't the foundational belief be that we have a soul that has been sundered from our Creator by The Enemy during a primordial Manichean duel and keeping it separate is the highest sin and only by returning it to where it properly belongs are doing good?
It isn't like the only two options are "the Christian conception of a soul" and "the atheists rejection of the conception of a soul".
Imagine you walk down a road and see a small forest ahead and a group of people before that forest. They all talk about what is beyond the forest. They all tell different things. But this does not mean they are all equally right or equally wrong or that one may simply choose the version one likes best. There is something specific behind the forest and if everyone tells their own incompatible versions, then everyone is wrong or everyone but one. (Or maybe some of the versions are not that incompatible.)
If you sneak away, go through the forest and come back, you will see a very nuanced picture of who is saying what. For example you found a stream. Someone may not mention a stream, but from his tale you will see that he indeed was there, but in winter and missed the stream just a bit. Or someone may loudly claim there is a stream, but you will clearly see that the person never was there and is only trying to persuade you to buy a flask.
But if you never was there all these tales will look same to you. This guy says this and that guys says that; how to decide? Logically? But is it clearly impossible to merely take all those words, somehow analyze them and get a correct answer. The clues one should look for are not in the contents of the tale.
It isn't like the only two options are "the Christian conception of a soul" and "the atheists rejection of the conception of a soul".