You need YouTube Premium to be able to download videos to watch offline (plus see no ads)

Newpipe can also download. No need for bloated YouTube-App, Premium subscription or ti hassle with a command line tool (in case CLI's are not your thing).

As also mentioned by others, youtube-dl seems kinda dead. However there is a good fork/successor called "yt-dlp" which, in addition to other nice improvements, also somehow manages to work around the enforced heavy bandwidth limit by YT.

WTH, you don't, just use youtube-dl

I strongly recommend checking out yt-dlp. Forked from youtube-dl but has much quicker downloads.

Never heard of it. Does that work on a child’s iPad and expose videos via an interface that they can navigate?

It's just a command-line tool to download audio/video from youtube (and many other sites). You'd need to setup the iPad thing yourself, maybe using something like Plex?

Consider Jellyfin instead of Plex (doesn't Plex try to push "free" content in addition to what you add to the server?)

Plex has shifted over time to present their content more prominently. It got to the point that your own media isn't even displayed on the default landing screen. Had to re-teach the kids how to find their movies and whatnot.

I haven't had it running in about a year though, couldn't be bothered after a move.

Jellyfin looks nice. I'll have to give it a go. I am dreading having to set everything up again if I move off of plex, rather than just grab my docker-compose file and get going.

All you need is Vanced or NewPipe.

Or youtube-dl. Though I've been getting bandwidth-limited lately...

There is a fork, yt-dlp[0], that I've enjoyed using recently that has some mitigations for this issue[1] (see --throttling-rate)t

[0]: https://github.com/yt-dlp/yt-dlp

[1]: https://github.com/yt-dlp/yt-dlp/issues/985

…or you can just use NewPipe.

No part of what you just said is true.