It doesn't feel like an opportunity. It feels like a pointless excursion in physical suffering.
On the flip side of the coin, why bother to make things better if the world doesn't matter? Who cares what difference you make?
This is one of the first things I thought about. To claim and worry that existence is pointless would appear to be a paradox:
Your actual yearning for existence not to be pointless is proof that you give it meaning.
The people around you still feel, like you, and there are things to be seen, and experienced. Even if these things are illusory, or predetermined, they feel real and have actual consequences, so by definition, they are real.
If there's no reason or purpose, then this is simply a sphere of matter orbiting around a star in an observable physical universe that goes on existing, pointlessly. Those "real people" are just the latest generation of mathematically evolved cell structures that will reproduce more structures before dying off. Their appearance of being alive is an illusion--their brains are cell-based automatons, no more alive or of value than a rock tumbling down a hill.
That may be, but to call it an illusion doesn't change what yesterday felt like when you called it reality. What you choose to call it makes no difference, because it still is the same.
Think about it this way: If we can't tell the difference between free will and absolute determinism, then what is there to miss? And what if there is no difference between free-will as we know it and absolute determinism?
But value isn't real. The ultimate, objective conclusion on the physicality of the universe would be that morals, emotions, and social norms are illusions of the brain, evolved out of necessity for survival. That means there's no difference between a philanthropist donating to charity or a homicidal maniac killing ten people. To the universe, it doesn't matter.
But to us it does.
And apparently we are somewhat special in our part of the universe, as we get to experience it, and think about it, out of what appears to be pure chance. We even get to manipulate matter to our advantage and enjoy life. We get to ask these questions and come to our own conclusions.
Who cares what impact we leave behind? There's no eternal god to care, and future generations are robots who will live through their generation and die as we will, so their thoughts--nothing more than biochemical signals passing through some cells--have no meaning anyway.
But the real meaning resides in the now, not in the later when we are gone.
Without anyone to experience meaning, there is no meaning, obviously. Which is what makes the fact that we can experience it all the more meaningful. It's a better reason, in my opinion, to not waste the opportunity to exist. (I hope that makes sense).
Am I coming off as overly analytical here?

I don't mean to. This is just a realization that bothers and fascinates me, though I know it's nothing new.
It fascinates me, too. I want to wrap the universe and the meaning of meaning into into a tight little package, and I don't want to stop experiencing life, (because I like it more often than not).
What I can't comprehend, and probably won't is non-existence; but I think that's where you were going with this. What is the meaning of non-existence?