Not sure if I remember right but didn’t the French Nouvelle Vague at first avoided actual film score with using diagetic music only?
Most of them have non-diegetic music, but it’s often played around with, like Godard did with Duhamel’s score in PIERROT LE FOU (abruptly cutting it off and restarting, for example).
But Lars von Trier and Thomas Vinterberg’s “Dogme” project had this at first, i.e. no non-diegetic music.