It's funny that you would write something like that as if it was a useful statement. Reducing that much complexity in such a nonchalant way... But nevertheless...
> that humans give meaning to their own existance.
If you have time can you share what you think is the reason for why humans have a capability, the will to give their life meaning? Where does it come from? Why is their ability to give life meaning able to produce actual tangible results in their lives and lives of other people? If that ability even implemented through some genetic mechanism, why does the world work that way that it produces this type of genetics, that can create meaning? Genetics could have worked in any number of ways, why this one?
Would you say that love "exists"? Would you say that an integral "exists"? What about if there are no mathematicians that know about it or use it? Does it still exist?