Seems like a ban for anyone under 16 is in order and a separate tenant for 16-17 to help kids navigate their way through the minefield before they're adults makes sense.
My kids are involved in some activities that use other social media-like platforms for sharing information with kids and parents, posting videos/photos, and even includes some group chat features where everyone can interact. It's been great, but 1. it's a small, controlled group and 2. there's active moderation that's possible due to the small size.
My youngest has learned to draw, and is really, really good at it, due to some amazing content on YouTube. They love to sit for hours drawing both following along and using it as inspiration for their own art work. But we all know how must of a disaster YouTube can be.
My life has also been heavily influence (good and bad) by having access to BBS and early Internet chatrooms and forums begging around age 10. I was lucky in that my father was involved in the 80s and 90s telecom boom so I had access to a lot of things (with and without my parents approval) before they became mainstream. I think overall it made me a better person getting all that crap out of my system early.
I don't want my kids to miss out of opportunities like that, but I also don't want them being sucked into the algorithm-driven shitfests of Instagram, TikTok, YouTube, etc.