Simply eliminate recommendation systems. All of them; social media, news, shopping, the lot.
This kills doom scrolling, this kills these weird echo chambers where people look up a topic, and end up in a doom feedback loop most cults would be proud of.
If you don't search for it, you don't see it. Full stop.
This would pretty much break the back of the US tech firms in many areas.
I read an article from long ago in the very earliest days of youtube where they came up with a simple new recommendation system and it increased the chances of someone watching another video by something like 17,000%.
That was a simple one to drive traffic. But now, it is getting far more insidious. If you are a man looking at comments on a he said she said relationship video, you will generally see comments supporting the man's side. If you are a woman, you will see comments supporting the woman's side.
Just kill this sort of algorithmic behavior.
These dark patterns are nasty. If you go to that big shopping site, and look up something like, "replacement battery for pixel 7 pro", you will get a screen mostly of the correct item. If you sort by price (the last thing they want you to do) you will get a screen full of spatulas, insoles, and things which they very much know you are not looking for. They want to train you to not sort by price.
These algorithms are toxic to human society. They are a huge reason we are seeing such insane polarization in things like politics, but also why you have people feeling marginalized and attacked, when it is just influencers telling them that this is the case. I live in a place where certain very tiny group rights are not very well respected. I had a member of this group telling me they are going to leave before the government kills them. WTF? While my local government doesn't particularly like them, it isn't sending out death squads. Not only is their mental health more threatened by this sort of social media crap, than by the behavior of the government, the government itself is responding to people who are doom looped into hating this particular group.
This sort of crap is poison all over the world. Under 16 bans and other crap is a tiny step, but the reality is that if the poison is there, it is still bad, and teens will still end up accessing it in droves. If the poison is removed, the age ban largely becomes moot.