Apple Music Trial and Consequences

Yes, the trial of Apple Music would include the matching component that either matches or uploads your existing music to your iCloud Music Library. Ordinally that shouldn't introduce duplicates to the library, not least because iCloud Music Library rejects duplicates. See Identify cloud status icons in your music library on your Mac or PC - Apple Support. Are you seeing a local original file marked as a duplicate alongside a cloud track marked as Matched AAC. This might happen if you first enabled Apple Music from a synced iPhone and uploaded its contents, before enabling sync library on the computer.

Did you actively cancel the automatic renewal of the Apple Music subscription? Saying "If I sign up for the TRIAL only, then not subscribe" makes it sound as if you may not have taken this step, and might explain why your library hasn't reverted to its pre-Apple Music state.

Before trying to clean up I would suggest you backup all your media so you'd be in a position to restore things as they were if needed. See Duplicate songs in iTunes/Music - Apple Community for advice on deduping. Turning off Sync Music, if currently on should revert to your locally stored music, along with any unhidden purchases that are only in the cloud.

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See If you want to cancel a subscription from Apple - Apple Support to check for certain if you have an active subscription. I think the matched tracks are higher quality matched tracks that are perhaps in the cloud rather than stored locally on your computer. Select a track and press Cmd+i to get Song Info, then look at the file tab to check. Compare with its partner.

Should you wish to you can delete the 192k versions and download the 256k matched copies which should continue to work if and when you cancel any active renewal and the subscription expires. You must download anything other than purchases that is in the cloud, and that you want to keep, before the subscription expires.

See Turn on Sync Library with Apple Music - Apple Support for details of how to turn on, and therefore off, Sync Library in both your library and your device.

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The 256k tracks are going to take up a little more room, but they are better quality than the 192k tracks. The only potential downside of trading up is that occasionally the store will mismatch, giving you a clean version rather than an explicit one, for example. That's why I suggested you backup everything before thinking about deduplicating the library.

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