In the past, when I several times accidentally deleted my Lightroom catalog, the Apple Time Machine has proven to be a completely reliable/usable backup for the Lightroom catalog. "Experts" warn to make the Time Machine copy only when Lightroom is not operating, which makes sense to me.
Now, I have the Time Machine copy, the Lightroom-generated copy on a different drive, and the overall clone of the entire computer to choose from.
Fortunately, I haven't accidentally deleted my Lightroom catalog in several years.