[Fang_]

Nice web ui aside, if I'm not mistaken youtube-dl already supports this kind of usage. You can `youtube-dl --download-archive archive.txt https://youtu.be/your-playlist` and it'll keep track in the archive.txt of everything it's already downloaded. Supplement with authentication options as necessary, set up a cronjob, done.

[itsyaboi]

It's even simpler than that, just give youtube-dl the channel name and it will download all videos skipping any that already exists in your current directory.