imo, life has as much purpose as stars have: none. it's the wrong question to ask. life is simply there, just like stars are there. it "materializes" when-and-where there are the right conditions (a narrow spectrum of energy gradients), just like stars do (the spectra are extremely far apart, of course).
If we accept your interpretation, then I think we must conclude that the purpose of life is to hasten its own extinction, by accelerating dissipative processes.
If we humans perish, our knowledge could survive us. What we have found out about how nature works transcends our species. That is not a good justification why life exists, but at least this reason is not limited to humans, like all other ones.
And if there is no one else that can use our knowledge, and no one comes after us, life was pointless all along.
You have already admitted that individuals may enjoy life and find much meaning, so it seems only honest to append a very large qualifier to your "life is pointless" belief.
No there isn't, for a simple reason: I enjoy life, many others do, and those who don't generally want to enjoy it. The point is what we want. Not some external criterion we have yet to discover. (Some Christian fundamentalists make a similar mistake, believing there would be no morals without God —as if we haven't eaten the damn fruit already.)
Now there's this tiny little problem about resolving conflicts: we have yet to extrapolate a collective will from lots of individual wills in a way we'd all agree is "fair" —I believe we have demonstrated the absence of a general solution. The overlap however is quite comprehensive, so I have hope.
What we should do is defined by what we want. Most of us want life and humans to continue to exist. Therefore they should. It's that simple.
Intelligent life is so far subjectively the most amazing thing that has happened in this universe.
We are the only intelligent species on our planet, our planet is the only place where we know for sure life exists in our solar system.
Based on our limited observations we are also the only intelligent beings in our galaxy at least at this time period.
While intelligent life may have no interensic meaning we have the capacity to give our life and the life of future generations meaning, this trait is quite likely the result of natural selection.
We study history, cherish our past, honor our heroes and plan for a better future and this is a universal trait that we as a species share.
Saying that life has no meaning is a pointless argument there is nothing to benefit from making this assumption, in fact you lose everything.
And it's not true that everything up to now would be pointless. Advancements in technology, science, knowledge, etc. have all been enjoyed by those who are living and have previously lived. Any lack of future humans doesn't mean the benefits of those efforts were not realized or consumed.
Arguably humans make life on earth worse for most other types of life we are in contact with
Well, not exactly. Life on Earth's only hope of surviving beyond the decline of Sol currently hinges on some intelligent species developing space travel. They say, "life finds a way"- maybe we are life's way of getting all her species off this planet before it is engulfed by the sun.
If we get off our planet we will ensure the long-term self-replication. Without us it wouldn't happen and all life on Earth would sooner or later vanish.
If you do not have that drive, then it is natural to cull yourself.
you don't need to care about future generations in general, but you probably deeply care about the future of your children. if you do not have any (yet): i'd said similar things before i became a father. since i've had kids... my urge to preserve the well-being of my children specifically is absolutely visceral, and i can only assume (it does seem so) that other parents feel similarly. no parent needs to care about their children's whole generation, the urge to care is decentralized and spread over the whole generation of parents.
the next question might be: why would you care about your offspring? because parental care is a trait that helps carry the DNA which encodes it farther than DNA without this trait will get (all other things equal). in general, we care about (a few particular members of) future generations (our offspring) because people who didn't give a fuck about their own children died out.
Note: nothing in this comment should be taken as an endorsement of that. I'm just offering it as an example of people who are making an argument that we should not try to survive as a species.