The whole social media and under-18 argument isn't a problem with all social media.

Its a problem with for-profit social media. The companies use gamification to addict and create terrible trends for everyone involved.

Mastodon, peertube, lemmy, and federated media doesn't do any of these gamblification, gamification, psychological attacks, and more.

To be fair, the techniques should be banned by the FTC for deceptive practices, for everyone. But the kids angle is what's being gravitated towards.