In my opinion the only real survival is through maintaining pure bloodlines. Upon extinction of the body, consciousness dissolves back into the universe.
You're describing "true" death.
That can't happen to us. That happens only to the weakest souls of the worst Andrapods, who are not under Divine protection.
Souls of good people who are not SS are also protected to an extent by the Gods, and then reincarnated.
To answer broadly OP's question, our Afterlife, for now, is waiting to be reincarnated. In the meantime, our souls are kept intact by our Gods.
I say "for now" because this drastically change if you achieve even only the first level of the Magnum Opus.
At that point you probably won't even need to reincarnate and you can just live in the astral plane indefinitely, like the Latest Hero of Humanity, HPS Maxine Dietrich.
Still, you could reincarnate if you wished so. Or if Humanity needed you, I guess. I'm not an expert, I'm relaying what I've understood from the Clergy.