Banning access to social media for kids under 18 similar to how tobacco and alcohol is banned to underage people would be the more direct line.

This argument is quite close to what gov'ts are "trying" to do here! And I tihnk you'll find very few people ammenable to the idea that we should allow cigarettes to be sold to underaged people (even if in practice they still get access).

The argument on the "don't do the social media ban" side is quite an uphill battle if you dig into this metaphor too much

All "social media" that uses recommendation algorithms should be unavaliable to children.

At least give it a try.