ONLY IF YOU HAVE A FULL BACKUP OF THAT DISK ...
I would suggest using one of the command line partition editors (parted, cfdisk, fixparts) that you are most comfortable with to
- list the partition details
- confirm that you have all that information saved for reference, then
- re-save that disk's partition tables.
That should only impact the UUID, if even that.
In my estimation, it is possible that there is some kind of age-related issue (specifically ... too many disk reads, leading to block de-magnetization). Re-writing that partition table's impression on disk with no change should leave the disk data untouched, but the partition table accessible with greater ease.
It's just a thought, even if it is a bit extreme as a solution.
The only other thought I have is that there may be a need to specify a "quirk" as part of your GRUB boot configuration, that specifically addresses some I/O issues related to that particular model of drive. That is what I had to do for in order to properly used my external 4TB MyBook USB drive. References on that are detailed here.