Religion

'purpose' or 'reason' for humanity's existence, or a given human being's existence (beyond, as you say, simply being one generation, preceded by millions before it) ... to accept as a possibility. And in fact, the most likely probability.

In my estimation, we're just here, because we are ... the laws of physics and chemistry allow for 'life', and there's 100's of BILLIONS of planets in the universe, and the universe is 13B+ years old, and given this total 'surface area' of time and space, OCCASIONALLY higher/intelligent life forms evolve on one of those 100's of Billions of planets, and we just happen to be living on one of those planets, now, at the time when it's happening. Luck of the draw, as it were.

I think it's frankly HIGHLY unlikely there's any 'purpose' or 'reason' behind it, I think it's just a product of physics and chemistry.

I also consider the notion that we're ALSO so lucky (beyond just getting to 'live', in this otherwise almost entirely cold, dead universe) as for there to be some kind of magical and unknown/undetectable means by which 'our consciousness continues after we die' ... to be absolutely fantastical thinking.

I'd bet every single penny I've ever earned in my life that when we die, we just die, and that's it. It's virtually unfathomable to me that everyone on Earth above a certain level of education ... doesn't recognize that ... at this point in time.

Just the fact that 'we', and all the living beings on this Earth exist, is WAY more than enough 'miracle' to satisfy my sense of wonder.

I don't also insist on a 'purpose' AND 'an afterlife' ... that's asking for WAAAAAAY too much from this universe, IMHO.