Hi, @nick yoni
Thank you for posting in Microsoft Q&A forum.
To clear third-party updates from the SCCM console, first we need to unsubscribe from the catalog. To unsubscribe from a catalog, right-click on the catalog in the Third-Party Software Update Catalogs node and select Unsubscribe, but the existing updates aren't removed.
To remove the existing updates, we may filter all the third-party updates in WSUS console, and decline them, then the updates will change to expired status in SCCM console and will be removed automatically after 7 days.
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