Thank you!
View attachment 902226
It's mostly .jpg and .heic files. But I have found quite a few .numbers. Many of my Word docx show a generic preview but are empty rather than giving an error, and the same with a few .xlsx files. All of them appear to have been created and/or saved in spring and summer of 2019.
But my huge concern is the images.
Well the file listing looks right, though a bit confused about the folder naming; Compressed.Dropbox - Is this data from Dropbox? Perhaps you could redo load it from your Dropbox account.
Are these files all on an external volume? Does you Mac otherwise operate correctly? Is it possible to test if the files are accessible on another computer if they are on an external drive? I assume you have no Backup?
Are we certain the file extension is properly recognised? With that many ’.’ characters in the path, the .jpg may just be seen as part of the name. Try Get Info in Finder and see under extension.
File extensions don’t really mean anything deep down, but it may influence how a program like Preview tries opening the file.
If you have a broken text document you can try opening it with less in Terminal
less <file>
which should unequivocally show the contents of that file. Not so useful for an image since it’ll assume ASCII when showing the file, but you could use it to check a broken text document to see if the contents of your files appears to be intact.