Nearly every school (in the US anyway) has some sort of online portal that kids log into to complete or submit assignments that can be used to embed or host videos.
my daughter's (kindergarten) assignments are embedded youtube videos. There's also "suggested videos" after they play that can send her down a rabbit hole if we aren't watching (we have two toddlers as well so attention is divided).
YouTube used to have a configuration variable in the embedded player to disable these end of video suggestions. Then they chose to stop respecting the variable. Then they started flooding all videos with ads.
> my daughter's (kindergarten) assignments are embedded youtube videos
My seven year old has Youtube blocked on the computer he uses, we saw too many rabbit holes so that was that.
He wants content, he comes to me, I youtube-dl it, he has VLC
It's content from the school, on a tablet owned by the school that I have no administrative control of. Besides changing schools, I don't see many options.