well theres nuance there too>
I have to train them to be on the web. Its basically a skill they will need to learn.
Amazon actually has pretty solid controls for kids based on age. Its really solid. But as my kids get into gradeschool they cant just be using an amazon firetablet. They are having to learn how to use a laptop, touchpad, typing on a keyboard. My kindergartner literally gets their own login at school. Heck its how they do some testing now (dont get me started)
They dont watch a lot of youtube now. I tend to curate shows and put them on plex for them. Or let them go ham on PBS kids which generally has good stuff. But theres a TON of crap out there, some of it really bad. Bad both as in "reinforces or actively encourages asshole behavior" but also as in "im downright trying to scare or expose a child to something way out of bounds".
So we have to filter for both. But what my eldest can handle is different from a younger kid. IE: Harry potter gives my younger kid bad dreams. But is fine for my older kid.
What i may do and install something like Zenarmor/Sensei or just go full MDM and whitelist only specific videos or something. Frankly it will likely be a combination of tools. And may just have to say no to youtube/youtubekids full stop.