I think that there is merit in saying that at the end of the day "we don't know". But I also think that's a shortcoming of atheism, not having a clear or unified positive position.
That's because atheism isn't a philosophy, a position, or a worldview, it's just a lack of belief in a god or gods. That's all there is to it. Atheists can have whatever philosophies, positions, or worldviews they prefer.
I think that the idea of not knowing why God exists (or holding a faith based position that God is eternal), and by extension viewing us as created in an organized anthropic principal-like universe, is a bit easier than the idea that we don't know why anything exists as it does, in that holding a belief in God still points us toward the unified idea that we serve a greater purpose. Rather than purpose being more individually determined (my purpose on earth is to be happy for example). What do you think about this last statement
@FrumiousBandersnatch ?
If 'serving a greater purpose' is what floats your boat, that's fine. I (and, I suspect, many others) prefer not to be an involuntary servant. It seems that some people need to be explicitly given a 'greater' purpose, told what's right and wrong, and how to live their lives; and some people don't.
"His intent was that now, through the church, the manifold wisdom of God should be made known to the rulers and authorities in the heavenly realms,"
I tend to view this as, in a Christian view, we've been created to display the glory, wisdom and beauty of God and Gods creation for essentially the universe and beyond to see, and to be inspired by. And that creation was essentially made to display the glory of God as Gods image bearers.
When we compare these ideas. An atheist approach of, you live maybe to be happy, or to help others, or maybe not for any particular reason at all, compared to the idea that you were created to shine. The atheist position, without something more attached to it, I think it feels kind of non-inspiring or empty.
As I said, there is no atheist 'position' - any more than there is a 'non-stamp collector's position', or a 'non-believer in the monster-under-the-bed position'.
Personally, I'm happy not to be in thrall to some deity or the product of its need for approbation and appreciation (from its own creation?

). The universe we see, the planet we live on, and the creatures on it are all entirely consistent with being the product of a simple set of physical laws, and mix great beauty with great horrors. We're one of the most complex things it has produced, so we can wonder about its origins, and make up stories about it, and it seems to me these stories are clearly the products of human imagination.
But seriously, if God is supposed to have created the universe, who are these other "rulers and authorities in the heavenly realms" he's showing off to?
Do atheists largely prefer the idea or belief that we don't serve a greater purpose? or do atheist beliefs vary and perhaps some do view a greater purpose? And what might that greater purpose be?
Atheist beliefs, philosophies, worldviews, etc., vary - all they have in common is not including a god or gods. If you want to know if someone thinks there is a greater purpose, you should ask them. Personally, I don't; I have my own purposes in life, and I find this apparent obsession with 'greater purpose' suggestive of some deep insecurity.
And that's what thurwood or whatever that guy's name is was really getting at when he brought up the rabbit in the hat
Huh? you've lost me there...