For proper desktop Linux in that price range a used surface is a choice. It’ll be bigger and less battery life than an android tablet and I don’t know what the fan situation is in the generations in that price range now.

Another option is go with an Android tablet that has LineageOS support. You get fullish access to the system, but the system is still Android, so depends on what you want if that works for you.

The first one would have deleted nothing as it needs to match the whole name. I recommend running find with an explicit -print before replacing it in place with -delete or -exec. It’s good to remember that find has a complex order dependent language with -or and -and, but not maybe the best idea to try to use those features.

Jellyfin was forked when emby went closed source, I don’t think it had anything much to do with any specific event at plex

Don’t give it internet access during setup.