systemd style, using system-wide user units /usr/share/fonts/ into ~/.local/share/fonts/ after concluding that the Firefox flatpak doesn't play nice with system fonts/usr/share/glib-2.0/schemas location.
# Automatically generated by systemd-xdg-autostart-generator
[Unit]
Documentation=man:systemd-xdg-autostart-generator(8)
SourcePath=/etc/xdg/autostart/Discord-gidro.desktop
PartOf=graphical-session.target
Description=Discord
After=graphical-session.target
[Service]
Type=exec
ExitType=cgroup
ExecStart=:/usr/bin/flatpak run com.discordapp.Discord --start-minimized
Restart=no
TimeoutStopSec=5s
Slice=app.slice