This may not be your point, but I want to point out the VLC app on iOS provides a target for saving files, including mp3, for offline playback. https://ytmp3.c

This may not be your point, but I want to point out the VLC app on iOS provides a target for saving files, including mp3, for offline playback. https://ytmp3.cc/ https://ytmp3.cc/ provides a general purpose online youtube to mp3/mp4 conversion service with no fee or registration.