Everything lacks the basics, and nothing reads system-level e.g. content rating restrictions, it's all per-service and per-device and it's maddening.
Worse, the single most-useful parental control possible, an allow-list, is often absent from TV interfaces and steaming services. Allow-list just the PBS app on AppleTV? Impossible, there is no way to do a case-by-case allow list. Allow-list only the handful of non-brain-rot children's shows on Netflix? Nah, it's just by age rating. Et c.
[EDIT] Our solution, after years and years of banging our heads against this? App-installation blocked everywhere, no YouTube on anything, all streaming services cancelled because they're such a pain in the ass, and the kids have a large curated set of pirated content served by Jellyfin that they can watch when they get TV time, including some things pulled from YouTube by yt-dlp. If we want to one-off stream something for the kids outside of that set of content, we "cast" it from a parent's device.
The non-piracy alternative would be to go back to discs for everything, I guess.
Standard ways of interacting with "modern" media services are just awful, if you're a parent. They're so bad that it's easiest to simply abandon them.