How does the collective work?
They’re all jacked into the boards constantly meme-ing each other.
That’s how the whole thing got started in the first place too. You had a weird cult like Qanon get memed into existence and then they got Neuralink. Then the cult became a malignant superintelligence that set about conquering the universe to exterminate the Satanic pedophiles.
“We are Borg! Resistance is futile! Where we go one we go all!”
Something like that... very easy to imagine. We are close.
Seriously though... take an online cult and add Neuralink and something like the Borg could actually happen.
I can't think of any where a civilization coalesces or evolves into one being and that gets explored in depth; only where it happens briefly "and then they uploaded/transcended/melded with the God-entity, the end" style. I suspect it would be hard to imagine being in a single superintelligence, I can only think of them seen from outside by ordinary humans. There are a few I can think of which have one-mind/hive-mind ideas on the small scale:
Starship Troopers, the enemy bugs are insect-style intelligences where only the queen is really sentient and the rest are worker-drones.
Joe Haldeman's Forever War ends with a reveal of the enemy being a hive mind of some kind, and it was all a mistake. Seen from the human side with no exploration of the enemy except that they exist.
Peter F. Hamilton has this idea in a couple of his books; one is Morning-Light-Mountain[1] which is an alien hive-intelligence which outcompeted all others in its solar system. The other is a trans-human faction starting to go the same way, "multiple-people" who clone themselves and have brain implants to sync their brain state into one mind shared between all their clones. Only on the small scale of a few dozen bodies, not a competitive intelligence. They're smaller plot parts in large space operas.
John Windham's Midwitch Cuckoos, the alien children are believed to be a hive mind, as teaching something to one of them turns into something all of them can do. Also seen from the outside, we never find out about their origins or the adult aliens.
(In the film Avatar, the aliens have a tree where they can tap into the wisdom of their ancestors, it turns out to be a kind of hive-mind of the dead).
[1] https://peterfhamilton.fandom.com/wiki/Morning-Light-Mountai...
[2] https://classicsofsciencefiction.com/2019/03/01/rogue-farm-b...
If we define life as an entity that strives to perpetuate itself, then the fact that we are separate individuals is just a hack to make us evolve and survive in a harsh environment. After some level of technological advancement, a futurist civilization might simply converge into a sole being, an unified intelligence.
I'll wait for the science fiction experts to point me to some books exploring this idea :)