SOLVED: Jellyfin Media Player Linux never shows subtitles

[Host-in-the-Shell]

I haven't installed Jellyfin on Arch before, as I host it using Debian, but I don't see anything there about a bash script or pointing towards ffmpeg. I think you're reading some steps that are beyond the Arch section. What I imagine the installation process would be, is something like:

sudo pacman -Syu jellyfin-server jellyfin-web (which should pull jellyfin-ffmpeg as a dependency)
sudo systemctl enable --now jellyfin

and that should be it.