[Hobadee]

Kodi isn't a media server. Plex isn't FLOSS. Emby is what Jellyfin was forked from, and barely classifies as FLOSS anymore, and isn't as popular as Jellyfin from what I can tell. There isn't really anything else that I am aware of. Jellyfin being the #1 FLOSS media server makes sense to me, although I don't think there are really any viable #2s.

[saint_yossarian]

Kodi does have bultin server functionality (both DNLA and a web interface), it's just less commonly used that way, and I don't think transcoding is supported without plugins.

[amiga386]

I tried it some time ago and found it was useless in that role.

Kodi is 99% a TV-like frontend to a local-disk media collection, its web interface is an afterthought, its performance for remotely served media is atrocious.

Jellyfin, Emby and Plex are media servers first and foremost.

[NoGravitas]

I actually use Kodi 90% as a front-end to Jellyfin. If I only watched or listened to my media at my TV, just Kodi and a SMB or NFS share would be fine. But with Jellyfin I have the same media everywhere. This is somewhat more important for music than for movies and shows.