Something to remember with the social media thing, which all the experts say is key:
It's not just about the content. Comparing apparently perfect lives, bullying, etc.
It's also about the way it changes brain function (gaming does this too.) It means kids don't find the same satisfaction from doing other things, and they experience withdrawal symptoms when they are off sm or gaming. It works the same way as gambling addiction, and if you think about how much time many kids spend on sm, it is like they are at the slot machine all day, every day. it's in their pocket.
It's also the time they are not doing other things. And actually opposite things. It's the time they are not with other people, building real relationships. Online relationships don't work the same way and don't have the same kinds of fulfilling outcomes.
it's the time they are not alone with their thoughts, or bored, or resting and sleeping, even.
And it's the time they are not playing sports, baking, reading a book, noticing their mum needs a hand and pitching in, etc.
Hours out of the day that used to include these other things, plus what is really a state of addiction.
It's a huge change in brain function, not just exposure to bullies or bad media.