Brave New World by Aldous Huxley
Spoiler alert for a book that’s old enough to be your grandfather: the one guy who maintains his individuality in a brainwashed, homogeneous society discovers he can't deal with any of it, and ultimately dies as a result.
You would not be that guy. He is far and away the worst-case scenario, and a rare one at that. Look, I get it, we all like to think we’d be the one to break the mold, to see things as they really are, to defy the World State. But in reality, it’s far more likely that you're going to be just another cog in the machine, tripping on soma and having bi-weekly sex parties with strangers, and that’s just the way it is.