>if for instance the algorithm was 'dumb' and just showed friend feeds and feeds specifically selected to follow?

That is how it used to work on facebook But social media was still toxic to teens even back then from the pressures they'd put on eachother, expectations for posting, etc.

That is making an argument that teens shouldn't interact since that generically describes many teen's lives at school. I don't know that we have good studies on 'dumb' social media vs weaponized social media compared to normal interactions for the target group.