lost Lightroom catalog that was synced, can I get the edits back?

Johan, if the extensions have to be different to allow Syncomatic to work, that's a problem here. When smart previews are downloaded into the new catalog, the catalog retains the original file names. So importing the original files from the backup will result in same-named duplicates (one "missing" with a Smart Preview containing the edits, the other not missing but with no edits, and both having the same name, including extension). Do you know if Syncomatic works in that scenario?

If that doesn't work, an alternative approach could be to import the original files from their backup into the Lightroom desktop app, which should replace the cloud smart previews (suggest testing that on a small set of images first, checking in the Lightroom app that the file sync status has correctly been changed from Smart Preview to Original). Then when the new LrC catalog is created and synced, the originals will be downloaded, complete with the original edits. The obvious problem with that approach is that there would presumably be a need to temporarily purchase additional cloud storage space in order to facilitate the upload of all the originals from the backup (assuming only 20GB is currently available as part of the subscription plan). CARE: If planning on using this alternative plan, it's important to setup the download location (and dated folder structure) in LrC via the Preferences>Lightroom Sync tab....this must be done before enabling cloud syncing in the LrC catalog.