I want to stop using iTunes Match, how do I do?

The matching part of Apple Music that covers your own media cannot be turned off. You can however have more than one library, only one of which you enable for iCloud Music Library. I have a primary library with about 50,000 tracks and a smaller iCloud Library that has about 9,000. The second one is shared with my Apple TV, HomePod, iPhone, iPad and three computers. See Open a different iTunes Library file or create a new one - Apple Support.

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Did you turn off iCloud Music Library in the primary copy before you closed it?

See About iCloud Music Library icons and status - Apple Support. Using the Songs view you can sort the library on iCloud status. You can select and remove what you want from the cloud list. You only have to download what you want to. I would recommend you keep any iTunes Store purchases unless you actually want to hide them from all of your devices. My iCloud Music Library is mainly my own purchased/matched/uploaded content with around 500 Apple Music tracks added to the library and I can stream anything else I fancy without adding to the library.

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