It is heavy handed on the wrong side. How about heavy-handed regulation of the Social Media platforms? Not content regulation, but operations regulation. I'm pretty sure bots and ai-spam can be both easily flagged and banned, something that would have a positive impact for minors and adults alike. But the platforms won't do it, because these drive engagement and keep their stock value up.

Also, including the mid-teens (15-16) into the regulation may have a generational negative effect. This is the age you start to get interested in the world and how it works. Social Media is the primary medium teens use to get this information, having eclipsed traditional media (magazines, tv shows, radio shows etc.) Banning Social Media for these ages leaves a gap in newer generations maturing to adults.

But maybe that's by design? I.e. make new generations indifferent to the world around them, and also prevent them from building resistance to (home) propaganda spread through Social Media.