Personally I've been in favor of heavily restricting or banning social media for anyone below 15 or 16 (or even 18, for that matter) for a long time. To me it looks like these platforms do almost nothing but harm, regardless of parental intervention, because the parents are often clueless as well.
However, YouTube is a major source of educational content, a lot of which can be legitimately useful for both school and private life. Same thing with Reddit, but not so much 'educational' as maybe informational. I'm not sure about straight up banning these two. Unlike social media (I wouldn't call YouTube or Reddit that), they actually serve some positive purposes.
In cases like these I think the best solution would be to find a middle ground, e.g., let children browse or watch, but not post. Or create sections for kids and actually put in the effort to moderate them, as opposed to YouTube Kids featuring multi-million view suggestive or straight up erotic videos, as well as scam and pornographic ads.