This was such a frustrating read because I agree with so many of the problems he identifies with social media, but I found his reasoning deeply flawed.
To the extent that this is a diatribe about how unpleasant social media is in his personal experience, I was mostly onboard, but the difference, I think, between a rant and a book is rigor.
His citations were mostly news articles and wikipedia entries, and he relies heavily on a superficial understanding of popular, flawed studies like the Stanford Prison Experiment. He makes bold, sweeping, and imprecise statements about the a number of things, particularly the nature of addiction and how addicts behave, without any backup or indication that he is speaking in any way besides entirely off the cuff.
I was disappointed as well in how stuck his reasoning is within the frame of capitalism and tech solutionism.