I can speculate that there may have been stiction, and now it is unstuck, but came unstuck in a very damaging way, and now one/some of the heads are weak or damaged.

Hiya,
In a similar scenarios to yours I often have had better results with Dmde than with R studio when I just want to recover certain files and folders.
The free version will allow you to recover single files one at a time. Try opening the drive volume to view the folder tree and then go for your most important files one at a time.