Oh my god... My client seems to have gotten the images mixed up, the thumbnail was a starving child on IV looking like a mummy, with zero context other than "rule" 😭
Unfortunately that's not really viable, since there's a heatwave currently sweeping over europe (thanks climate change <3) and his room is at 30 degrees centigrade even without any servers running.
There's always Plex and emby, but if the videos didn't play in jellyfin I doubt they will play in those two. You are probably lacking hardware support for the codec you're trying to play.
I signed with eID 🙋