Yes, I think Plex was an XBMC fork and Kodi is the new name of XBMC. Jellyfin forked from Emby, I think when it became closed source. I never used Emby. Plex always seemed to cost money in confusing ways and that turned me off. My initial TV just used NFS shares on a unix machine and a Netgear NeoTV box (~2009) but eventually the codec support was too poor so I moved to XBMC on the Shield and then a number of years later to Jellyfin server on Linux with Jellyfin client on the Shield.
Plex used to routinely offer lifetime pass for like $80 at Black Friday until recently, so that was just an obvious decision if you even remotely used it. If you’re only planning on using it on your local network you don’t need to pay for anything.
