How do you either delete or stop iTunes from duplicating music tracks?
I can't answer for stopping, but I have a fix:
Go to "View" (the tab at the top, dropdown), and press 'Hide Duplicate Items'.
If you go to the "Songs" tab in iTunes Music and click View > Show Duplicate Items from iTunes' menu, you can see all the duplicates you have and selectively delete the copies you wish to remove.
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