I tried Jellyfin, doesn't work for most things, went back to plex. Everything just works. My use case is pretty simple, family photos and videos but somehow that was problematic.
Jellyfin is good aslong as the content is not HDR and needs subtitles.... Also the chromecast support is very non-wife friendly
But if you use ASS subtitles, which are entirely unspecified and unsupported and only have a single working implementation that requires half of Wine to work correctly, well, then you're fucked.
Works on Android devices like the shield or libreelec on something like a pi.
Those native Android apps, be it jellyfin or plex dont handle subtitles wel, be it .srt or .ass
I've used clients on all classes of Apple devices, LG WebOS and browser. They're all quite problematic.
I still run it alongside Plex and give it a go every month or so but the same or new problems always arise.