eggnoggpi/files/etc/systemd/system/eggnoggpi.service

[Unit]
Description=Eggnogg Plus on a Raspberry Pi
Requires=nodm.service
After=nodm.service

[Service]
Restart=always
User=pi
Group=pi
EnvironmentFile=/etc/default/eggnogg

WorkingDirectory=/home/pi/eggnoggplus-linux
ExecStartPre=/usr/bin/mpv --loop-file=inf --background-color=black /home/pi/music.opus &
ExecStart=/home/pi/eggnoggplus-linux/eggnoggplus

[Install]
WantedBy=graphical.target