Since Sonoma upgrade music not syncing between iPhone and Mac

I am a songwriter and I use my Mac to record ideas; and I use Logic to produce songs. I manually sync my playlists to my iPhone - by ticking each playlist I want to sync.

Since upgrade to Sonoma my phone changed to automatically syncing (even after 2 days it was still preparing to sync). I eventually managed to change Music back to manual sync but the results are hopelessly erratic. Playlists are incomplete. I can't individually tick off the playlists I want to import to my phone - this facility is now greyed out on the music / iPhone sync page.