iTunes Match is a primarily a library syncing service. You can enable Sync Library/iCloud Music Library on multiple computers and devices which then all get the same set of music tracks and playlists. Additions, removals, and edits made in one place get repeated on any others seamlessly (we hope) over the cloud. In addition there is the potential, by no means guaranteed, for a lowish quality track on your computer to get matched with a higher quality version in the iTunes catalog, which may allow you to remove your current download, then download the better quality version which you can continue to use after terminating your iTunes Match subscription. This process may work with older 128k AAC DRM protected iTunes purchases, which was once a selling point for iTunes Match. This upgrade doesn't happen automatically and must be done manually. All of the other benefits (apart from upgrading DRM purchases?) are included in the Apple Music subscription service so there is no need to pay for both services at the same time. Apple Music also allows you to select content from the Apple Music catalog to add to your cloud library which you can use across any of your devices while your subscription remains active. Apple Music works better than iTunes Match with HomePod for, um, reasons.
As an aside the Apple Music for Windows app is a poor substitute for iTunes, making certain housekeeping tasks harder or impossible. Unless you are already wedded to it I would recommend reverting to iTunes by removing whichever of the newer apps you have installed and reinstalling iTunes if needed. While those apps are installed iTunes is limited to managing audiobooks and podcasts.
Tracks with apparently the right metadata aren't guaranteed to match up with content in the iTunes Store. And mismatches also happen. That said if you have a track that previously uploaded instead of matching you could try removing it from your library without deleting the underlying file, then add it back to see if it now gets processed differently. Make backups before you start.
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