Such arrogance, humanity isn't all that far beyond it's banging rocks together phase. We haven't even scratched the surface. There is so much more to learn.
No one has ever had the experience to be able to say.
Works of art that require thousands of lifetimes to complete. Deep understanding of the physical world. Exploring the universe. Much more.
Re: creating new beings. How long till you also get bored of that? Remember we're talking about quadrillions of years.
An additional thing to consider: if you could live quadrillions of years and still be able to perceive things that take thousands or millions of years to unfold, wouldn't you subjectively be living the lifespan of a normal human being? That is, your life wouldn't feel long to your mind, but normal (your mind would have to adjust to run more slowly). Wouldn't then regret your "short" lifespan and wish you could live longer?
I don't know whether this is something I would wish for myself. Maybe. I like being human. But maybe, who knows?
That said, what would you do with your quadrillion year long lifespan, assuming you're healthy during it? It's way past everything you can do and learn, and cosmic level events are not what the human mind can perceive as they slowly unfold...
I would like to live a couple thousand years though, as long as my loved ones get to be along for the ride. Though I wonder if my loved ones would eventually become my hated ones...