Transfering Music

I will ask you again to describe in detail what happens when you try to sync the music. I assume that you are running Catalina, Big Sur or Monterey. Is that correct? If you aren’t running one of those OS’s then you sync music via iTunes.

It should still work using iTunes or the Finder if you are running Catalina or higher. It would help if you would explain what happens when you try to sync the music to your phone.

have you read

Use the Finder to sync your iPhone, iPad or iPod with your computer – Apple Support (UK)