I'm not against what you're saying, but I also don't mean "like youtube for kids", I mean something we would legislate and build to completely replace the current internet.
I think it's a fools errand to try to keep building walled gardens and hoping to keep the vermin out. What I'm proposing is a literal second internet. No ads, no adult content, no third party tracking, and with training wheels.
We need children to understand what internet scams are, we need them to understand how to use a search engine, and we need them to develop behavioral norms with respect to social media.. we can't do that by just yelling at them to go outside.
So I earnestly want to know how much this would cost.