The Lightroom Classic catalog FAQ web pages states:
Starting with Lightroom Classic 11, Lightroom Classic stores some additional information in a new file, with an extension of.lrcat-data,along with the catalog file. This file is located in the same folder as your catalog file. This file contains important information about your photos and edits and should be included in any backup regimes you may have.
So, why doesn't Catalog Backup also back up this "file" (which is really a folder in Windows, with several subfolders)?