MyBookWorld External Drive Public folder is missing my Jpegs

Many, many years ago I purchased an external MyBookWorld to backup my photography. I just dragged and dropped about 7 years worth of folders containing thousands of RAW and jpgs from my 2013 Mac Pro into the Public folder on the MyBookWorld.

The folders all copied over and I can’t be sure all these years later if I checked to see if the photos copied over as well. Being clueless and assuming they all copied over I didn’t think much about it. For safety I copied the same files to another external and thought I was being safe. Well that second external died and no more photos. Whoever I sent it to said sorry we cannot recover.(Quite a while back. and cannot remember). So you can imagine my horror when I checked the MyBookWorld and opened the Public Folder and checked and rechecked 7 years of folders and found not one jpg or Raw file in any of them. Yes – all the folders are there but NO images!!

Most of the photography is client and family archives and cannot be replaced. Is there any possibility of retrieving these images or am I just plain out of luck? Any help or suggestions would be most grateful.
Thanks.