It's whatever you want it to be.

That is the main difference between how an atheist and theist thinks. Many atheists realize that they have the power to generate any kind of purpose/point that they want.

There's a number of related questions that seem to arise around this.

Is this self-generated point-to-life valid?

It's again a matter of opinion. Some people may find meaning in the journey, as opposed to arriving at the destination. Just because someone else may think the destination is important, doesn't mean the pro-journey person is wrong.

Pointing out that life has no purpose/meaning without an afterlife doesn't make much sense to us. If there is no afterlife, this life is automatically worth infinitely more, because it is a rare commodity. If diamonds were as common as dirt, diamonds would be as cheap as dirt. This life becomes the only one we have, so we had better make the most of it.

Does it need to be "valid"? Why do you start with this requirement that it must be externally validated? Ultimately, it only matters whether it's valid to you./p>

Who decides whether survival is valuable or preferable?

No one decided this. Just like you have a survival instinct, that was biologically evolved into you, you also have a biological preference for pleasure over pain, and survival over death. It's not a question of having a philosophical justification. Thanks to your biology, you can't help but value survival.

What is the point of living if anyone who I help, or whose live I change, ultimately dies?

If we consider some science fiction for a moment, your help can have a ripple effect through the generations, from that person you helped, to the people that are subsequently helped, and so on. We don't know that humanity can't survive the heat death of the universe, so there's hope in that regard.

Back to normal reality, isn't it enough that you helped that person live a better life? That should be the goal, that is then accomplished.

Why do you listen to music? Do you have an ultimate purpose with this? For many things in life, we experience them without requiring "ultimate purpose". I don't need such a reason - that transcends space and time - to justify listening to a song. I just do, because I enjoy it.

Many religious people don't find these answers satisfying. The problem is that they're requiring "absolute" or "ultimate" answers in the first place, when none may actually exist. That's life. It may ultimately be a barren, pointless existence, other than what we create for ourselves, but if you don't like that answer, that doesn't mean that a god exists. That's merely wishful thinking.

For the rest of us, our own meaning and purpose is more than enough.