I've installed the "official Jellyfin Media Player". This is just a browser embed, i.e. not better at all. In fact, it's worse, because it embeds Chromium which supports even less media types than Firefox. Through "Flatpak", I've installed the old QT Jellyfin Desktop, Delfin, Fladder and Switchfin. All have native players, good. Two of them don't even start. The two other crash after playing thirty seconds of video. Great, exactly what I expected from a monster like "Flatpak". Thread continues.