Hello starbux48,
Thanks for asking the Apple Support Communities for help with syncing music.
With macOS Catalina, you will need to use Finder. This article will help: Use the Finder to sync your iPhone, iPad, or iPod with your computer - Apple Support
Make sure you disable Sync Library because if this is enabled, syncing with the Finder may be disabled. "If you use iCloud or other services like Apple Music to keep your content up to date across all of your devices, some syncing features through the Finder might be turned off."
This article will help to make sure you disabled Sync Library: Turn on Sync Library with Apple Music - Apple Support
Thanks and have a wonderful day.