Syncing iPhone with Finder hangs in Catalina

My iPhone 8 stopped synchronizing through wifi. I tried to restore the setting with an USB-connection, as mandatory, but the procedure stops at about 90% and hangs indefinitely. I use the synchronization solely for audio (music, podcasts and audiobooks). Any addition or update to the playlist on my Mac should appear on my iPhone. I suspect the problem is with my Mac, not with my iPhone.

iCloud synchronization of mail, messages, pictures, e-books, iApps works flawlessly.

The system log says this:

Oct 5 15:43:24 MacBook-Pro-2 Music[873]: objc[873]: Class PDFToRasterImageRef is implemented in both /System/Library/PrivateFrameworks/AMPLibrary.framework/Versions/A/AMPLibrary and /System/Applications/Music.app/Contents/MacOS/Music. One of the two will be used. Which one is undefined.

Oct 5 15:43:25 MacBook-Pro-2 Music[873]: objc[873]: Class asn1ReceiptToken is implemented in both /System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Frameworks/CommerceCore.framework/Versions/A/CommerceCore (0x7fff8aa806b8) and /System/Library/PrivateFrameworks/CoreFP.framework/Versions/A/CoreFP (0x10eea62a8). One of the two will be used. Which one is undefined.

I suspect this is the culprit. I tried replacing the Music app with Time Machine but Finder doesn't allow this. Messing around in System/Library is beyond my knowledge. So, what could help? Restarting Mac and iPhone didn't change anything. Both have the most recent system version.