It is clear that rituals and sacrifices can bring people together, and it may well be that a group that does such things has an advantage over one that does not. But it is not clear why a religion has to be involved. Why are gods, souls, an afterlife, miracles, divine creation of the universe, and so on brought in?
I am not interested in the afterlife. Religion is supposed to be about losing your ego, not preserving it eternally in optimum conditions.
I'd like to see a ghost. It would confirm there's an afterlife.
I don't believe in an afterlife, so I don't have to spend my whole life fearing hell, or fearing heaven even more. For whatever the tortures of hell, I think the boredom of heaven would be even worse.
Do for this life as if you live forever, do for the afterlife as if you die tomorrow.