We can agree on that before our birth, there was nothing (which wasn't bad). We can agree on that during life, we can go through periods of time when we are not conscious (deep sleep) which is similar to this "nothing". And we can agree that when people die, their brains stop functioning and their bodies decompose or can even be cremated in which after there is literally nothing left of them except ashes. But then what happens after that, after we die? "Ooohh, we can't know, since no one has come back to tell us, maybe the consciousness survives, like some magic, wooo." The older I get, the more this kind of thinking starts to reek of ego's narcissism wanting to feel special (or more likely, a buffer against fear of death because its nicer to believe we are special than be scared). No one has come back to tell us about it because there is no more functioning brain and body to generate thoughts and speech. Just like no one can tell you before they are born what it is like to not be born yet. It's the same thing.

You say that consciousness is a miracle, that this can't be all there is, that 80 years is not enough. First of all, nothing actually guarantees that you will make it to 80. "Do not regret growing older. It is a privilege denied to many.” Second, at least you get to experience this life at all in the first place. Trillions of potential human beings never get to experience anything at all. "Everybody dies, but not everybody lives". The assumed "nothing" after death is the same nothing that was there before you were born. Did that scare you? Of course not.

If consciousness/awareness is all so magical, why are we capable of shutting it off so easily with anesthesia? During deep sleep, your consciousness is off, but guess what isn't? Your brain. It works 24/7 your whole life. If you damage some parts of the brain, it damages your consciousness. It's even debatable that chimps have some kind of consciousness too, and they have like 98% the same DNA that we humans have. Do chimps go to heaven too then? What about other animals? The ones who are not conscious? What happens to them? And why wouldn't that same thing happen to us? We all are here from the same source as they are, from DNA. DNA is here because it survived and reproduced. It's not on purpose, it's just how it functions and since it didn't die of extinction, it's still here doing its thing. Dinosaurs (created by DNA too) where here for 260 million years, now they are gone. What was their point?

People also don't think this through. If this life is not the only one we get, that our consciousness survives, that means that essentially we are immortal. That means we are forced to exist for eternity. With no escape. No possibility to return to the pre-birth state (which was nothing). People don't think it through what kind of absolute HELL that would be like. You won't get bored in 1 000 000 years? That's fine. Billion years? Maybe. Well honey, billion years is NOTHING compared to eternity. See what I mean? And if that eternity would include pain then oh boy we are fucked. Consciousness better not fucking survive our deaths, because otherwise, we are literally in hell. Watch the Black Mirror episode "White Christmas" and you know what I mean.