Tube Archivist is quite heavyweight as it's meant to do heavy full archiving of YouTube channels and search through positively huge libraries. I'm getting the sense that it's a data hoarding tool, not a casual web video watching tool. I found that I just want to add a few channels to my media library, for which I use Jellyfin already.

For people looking for a more lightweight option of that kind, I run the following script hourly [1]. This script uses yt-dlp to go through a text file full of YouTube RSS urls (either a channel RSS or a playlist RSS works for channels where you're only interested in a subset of videos) [2] and downloads the latest 5 videos organized in folders based on channel name. I watch these files by adding the output folder in a Jellyfin "Movies" type library sorted by most recent. The script contains a bunch of flags to make sure Jellyfin can display video metadata and thumbnails without any further plugins, and repackages videos in a format that is 1080p yet plays efficiently even in web browsers on devices released in at least the last 10 years.

It uses yt-dlp's "archive" functionality to keep track of videos it's already downloaded such that it only downloads a video once, and I use a separate script to clean out files older than two weeks once in a while. Running the script depends on ffmpeg (just used for repackaging videos, not transcoding!), xq (usually comes packaged with jq or yq) and yt-dlp being installed. You sometimes will need to update yt-dlp if a YouTube side change breaks it.

For my personal usage it's been honed for a little while and now runs reliably for my purposes at least. Hope it's useful to more people.

[1]: https://pastebin.com/s6kSzXrL

[2]: E.g. https://danielmiessler.com/p/rss-feed-youtube-channel/