Music from iPhone 12 to iPhone 16

Hello! I had lots of music (16 GB) on my iPhone 12 in the Apple Music App- but now with the iPhone 16 the Music is left... if you watch at "Downloads" in the settings there is 0GB. I had lots of iPhones till now but there has never been a problem with the music sync from the old iPhone to the new one. I also tried to connect the old one with my Mac, but he can find the iPhone but there are no songs shown?! If I open the Apple Music app on the old iPhone there are all songs there?! Whats the problem?! Can anyone help? The songs aren't songs downloaded mit the Apple Music app, these are old songs from iTunes (but there is no iTunes on my new mac possible to install)