I am concerned that you might think that your photos are contained in the Catalog.
an attempt to retrieve the photos
They are not!
You can retrieve a Catalog Backup and 'open' the Catalog in Lightroom, but you also need to have the original camera files available also.
thanks for help but all I have are gray boxes. I am not techy at all and really need to pull up these 20,000 photos. Suggestions?
Are there question mark icons on your folders or exclamation point icons on your photos?
If yes, then this might be the solution: Adobe Lightroom - Find moved or missing files and folders
If no, then this might be the solution: https://www.lightroomqueen.com/how-do-i-change-my-monitor-profile-to-check-whether-its-cor rupted/