Restoring a directory from the cloud

Unfortunately, a copy of the whole Catalog does not sync to the cloud. Only certain edited images - those in collections that you have chosen to sync out to the cloud, where they appear in corresponding virtual groupings. And, are only stored in cloud in the form of Smart Previews plus metadata, not as the full camera file that is in the local storage. Also such matters as editing History, and the organisation of images within folders on disk, are not represented in the cloud at all.

If you still have got access to the images that you had imported, but have only lost access to the Catalog you imported those into (and cannot retrieve that), then some of the editing info may still be OK. That is, IF the option was selected as you worked on the images, to Auto-save new changes out to external XMP. In that scenario those images on disk will have LrClassic editing metadata attached. On making a fresh empty Catalog and importing those images, the attached metadata will get read so that the latest available Develop edits are seen (rather than an unedited photo). That would not restore a lot of Catalog organisational stuff such as Collection membership, also Virtual Copies would not be restored at all in this scenario.

The very best approach is to get a Catalog back -  for example, if you had backed up the Catalog on closing LrC then that can now be extracted from its ZIP archive and opened.

However it is not clear to me whether you do still have the photo files (camera Raw or camera JPG, etc). FYI a Catalog backup only covers the metadata database concerning imported photos, and does not embody the imported photos themselves, which require separate backup provision. Worst case, if lost entirely from computer setup and no backups, photos may still be present on the camera card?