Two obvious sources of legal media for jellyfin are home movies and university lectures (which are generally creative commons licensed), both of which I serve on my family's instance. I believe recording broadcast television is also perfectly legal in the US, and there are still commercial products to do it.
The *arr software by contrast are pretty explicit about what they're for. e.g. radarr says it will upgrade a movie you have from dvd to bluray quality via torrent or usenet, which is almost certainly illegal. It does look like they don't distribute executables though, so their repositories contain only a detailed description of the knowledge of how to perform illegal activities.
I think the most obvious sources of legal media are bargain bin DVDs/BRs which you are allowed to rip for personal usage and backup. This would justify all the discussions about episode numbering and so on. I have a small mountain of discs in boxes in the basement, which I bought almost for free (looking at you 17 EUR DVD box set of Friends) and will never see the light of day because they're all comfortably copied on a NAS too.
Same for games, I have titles like RDR which I bought from a bargain bin while it was still very much in vogue for ~2 EUR. I can't use it as a copy but the supermarket bargain bin can be an eternal Black Friday for your media consumption.
The *arr software by contrast are pretty explicit about what they're for. e.g. radarr says it will upgrade a movie you have from dvd to bluray quality via torrent or usenet, which is almost certainly illegal. It does look like they don't distribute executables though, so their repositories contain only a detailed description of the knowledge of how to perform illegal activities.