I've noticed over the last year or so that my Facebook feed has changed dramatically - most friends now post rarely, if ever, and my feed is mostly full of ads, "full story in comments" articles, and AI crap. In turn, I've dramatically cut down how much I post. I now post around once a month and, a few years ago it was several times a week! The only thing useful about it is a couple of groups I'm in. Can't comment on Instagram & Twitter as I've never really used them and the likes of Tik Tok & Snapchat are alien to me (I'm old!). I then stumbled across this article which seems to sum it up perfectly.....
https://www.bbc.co.uk/worklife/article/20250722-social-media-user-changes-kyle-chayka-katty-kay-interview