Just remembered there’s stuff like Grayjay or Revanced?

I can’t tell you much as I haven’t used them myself but apparently Grayjay can play a bunch of videos from different sources. However there are mixed reviews and it’s android only. The ability to allow age restricted videos seems to be broken though so maybe that’s a plus 😂

There’s also some non-app based measures to manage YouTube without an account https://www.clrn.org/how-to-put-parental-controls-on-youtube-without-an-account/