That is a good proposal. Similar to that already is done partly. There is YouTube and there is YouTube Kids. Two different apps that provide same content, but YouTube Kids has more restriction of what content is shown. If there were children version of Facebook, Instagram, TikTok, that would really be great. I think it is not hard to create such versions or make "really working" restrictions of content with help of AI. If previously proper content moderation was the problem, AI should solve that issue and also it should be a cheaper solution.
Social media isn't completely harmful for kids, and a total ban would kill off some real benefits without even fixing the actual problem. So I also think this is a pretty good proposal and much better than France's previous broad ban.
We're living in the internet age, adults get to use social media for whatever they want, why not kids? I think people who support a total ban probably don't really understand how kids think. Or they're just parent who want things to be easier for themselves without really caring about what their kids feel or need.
Youtube kids actually works pretty well.