I’ve never had any issues with jellyfin. Maybe your use case is outside of what it’s for, but for watching series and movies it worked with everything I could throw at it for me.
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
Jellyfin is good aslong as the content is not HDR and needs subtitles.... Also the chromecast support is very non-wife friendly