En suivant les conseils du commentaire de @mpy, cela fait l'affaire :
# Ensure the settings file exists (not created on install but on launch)
# by calling vlc with an invalid value for the interface option.
# Does nothing except create and populate the file
# ~/Library/Preferences/org.videolan.vlc/vlcrc
vlc -I none
# Enable dark mode.
sed -i '' -E 's/#?macosx-interfacestyle=0/macosx-interfacestyle=1/' ~/Library/Preferences/org.videolan.vlc/vlcrc
# Disable icon changes (e.g. Christmas icon)
sed -i '' -E 's/#?macosx-icon-change=1/macosx-icon-change=0/' ~/Library/Preferences/org.videolan.vlc/vlcrc