perhaps as a specific kind of hunter, learning how to defend against threats, being particularly adept at memorizing terrain and resource locations and so on, then having a purpose would make you valuable to your community for survival.

This is definitely possible, good idea. It could also be a by-product of intelligence and/or consciousness. I think it is particularly useful to think about the period of time when self-awareness was becoming stronger and stronger. The dawning of self-awareness should have led to a cascade of effects, one of them, I suspect, also including "finding a purpose". In this sense, the survival advantage of "having a purpose" would be to avoid insanity. If you believe your consciousness is infinite and that you are here because "someone has a purpose for you" then you are going to be able to run your incredible complex software and apply it to things it was meant to be applied to: survival.

Will we find satisfying purpose in our lives from something other than religion?

Individuals already do this. Ideally everyone can find a vocation in this life that they deem to be bigger than oneself. For me, it is science. For someone else, it might be art or music or whatever makes them feel amazing inside. The meaning of life, on an individual level, is all about finding your own meaning.

Can we appreciate our role in evolution, species survival and intellectual evolution?

I think it is the most beautiful story. So, I hope so.