You are begging the question in in the original sense of the phrase "begging the question."
You start by stating your conclusion as an axiom! You state that "no human contribution matters because a different species already thought of it" as if that is necessarily true.
It isn't.
We choose what matters. I play Bach, badly. Bach already thought of that music, and many thousands, possibly millions of people have played the particular pieces I have worked on (The first suite for unaccompanied cello in Gmaj, the Prelude to the first Fuge in Cmaj from Book One of WTC).
Does my playing not matter?
I say it does. Furthermore, Bach's music can be encoded as a number. All numbers already exist. Bach did not create that number any more than I created the number that encodes this comment.
Does my comment not matter?
You find this general idea depressing, and so do many other people.
But it isn't "depressing" in an absolute sense. That's just a word we made up to describe a feeling many of us happen to have.