In Music, select Songs from the left menu bar. Choose File > Library > Show Duplicate Items. Browse and delete duplicate items.
Why are there duplicates in my Apple music library?
iTunes or Music may create duplicates if the same content is repeatedly added from outside the media folder when it is set to make copies of anything that is added to the library, or is added from an external drive that hosts the media folder if it was offline when iTunes or Music was launched.
How do I clean up my Apple music library?
Find the song, album, or music video that you want to remove. Touch and hold the item, then tap Remove. Tap Remove Download to remove the item from only this device. Or tap Delete from Library to delete the item across all of your devices.