There are infinite possible deities and faiths. If the premise is that one must believe in the correct one to be “saved”, there is no point, since there is no evidence to distinguish between said infinite possibilities.

Also, since we are positing that belief could save us, why should I not hold the belief that atheism will allow my consciousness to remain in another reality, or even simply another place in spacetime? Naturalism does not deny the infinite possibilities wrought by the unknown. (Well, the answer is shown in the first paragraph, but in case that didn’t convince you).

But let’s get serious now. You present a logical progression of propositions in order to support the final one. I think you’d agree that in order for such a form of argument to hold up, P1 must be true. However, it is simply a baseless assumption. There is no reason supported by evidence that any belief, atheistic or not, has any effect on what happens to consciousness after death.