Do not run chkdsk m8, you're stressing it out
Pick files that are the most important first, keep copying and hope that your drive lasts until you've got it all.
Spin down the drive might render it inoperable the next time you plug it in
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
Do not run chkdsk m8, you're stressing it out
Pick files that are the most important first, keep copying and hope that your drive lasts until you've got it all.
Spin down the drive might render it inoperable the next time you plug it in
I would recommend using ddrescue. It can copy block by block, can skip over slower or error prone regions to prioritize good sectors.
I used it to pull 2tb from a dying drive. It was able to pull 1tb in about 4 hours, and took about 2 weeks to clone the remaining 1tb. But it successfully pulled all data with no errors in the end. Saved my 8tb raid array.
If you can still read it, I would start just manually copying the most important files one by one.