It's all about triggering neural chemistry, fight or flight (fight being prevalent because of the inherent feeling of being "safe" behind the screen), pleasure, risk and reward, etc
These companies know 100% what they are doing, how addictive it is and how profitable it is.
This is also why they REALLY want access to kids, nothing to do with free speech, they KNOW a developing brain is easier to addict and much much much harder to treat for the addiction. They are building products for life (if it's free, you are the product being sold).
Now it's also about feeding the AI for even more "what ever" it is meant to do for us.....AI slop gets boring every quickly.
When I quit X, I gained over an hour a day just wasted on all the fight or flight BS that was feed to me
When I killed adverts on other social media platforms , made my profile more private, "blocked" every account with a "follow" or other types of engagement posts , even the ones seemingly part of a friends account, I found my Facebook dropped to around 1-2 minutes a day. I maybe post something 1-2 times a month.
I read actual books, teaching myself how to use a metal lathe and other hobbies, socialise more, and way less stressed and sleep better.