I usually scan my media with Media Elch before I move it into Kodi/Jellyfin then I know the files and folders have the right names and all Metadata is correct.
TV shows are grabbed, named and tidied with pyMedusa.
I use Kodi on a RaspberryPi with the Jellyfin add-on so if I watch something remotely then the watched status is synced everywhere.
If you’re using Windows then Foobar 2000 is great. I use it for manually managing and tidying my collection in addition to converting pretty much any format to any other format.
That being said, you can install it as a snap in Linux as well if that’s your poison.
Also using Jellyfin and it’s great.
Regarding the number of different clients, yes they have less than Plex but remember Jellyfin is a free product and is a considerably younger project so more clients will come in time.
I run a Jellyfin add-on with my Kodi setup and it runs great and streams to three of my mother’s LG TVs, one uses a web client as the official client hadn’t been signed off by LG, another uses the official client (LG run multiple versions of their WebOS) and the third runs the official client on fire stick from the Amazon app store.
Mama!!! Peekaboo is between two and two thirty right after this little piggy, please don’t mess with my schedule!
MASH was an interesting one. It was originally broadcast in the UK without the laugh track and it was so much better.
When it was eventually released on DVD here, there was an option to play it with or without the laugh track.
I was only a youngling when the series finished and I sobbed like a girl when it finished.
Heroes Fantastic first season, after that it was just horrific.
Spoken like a true AI!!! ;-)