Oh yea one more comment, this stdin redirection isn't really necessary in minecraft from the last decade. The minecraft server has a built-in RCON server runni

Oh yea one more comment, this stdin redirection isn't really necessary in minecraft from the last decade. The minecraft server has a built-in RCON server running on a separate port than can be enabled(https://wiki.vg/RCON https://wiki.vg/RCON), and once enabled can be interacted with an RCON client(like https://github.com/Tiiffi/mcrcon https://github.com/Tiiffi/mcrcon). So instead of redirecting stdin to a systemd process, you can also just leave stdin disconnected and use the built-in RCON server to do commands every so often.