Thanks cpt_paranoia. I did more research and found this post https://community.wd.com/t/data-volume-failed-to-mount/91074/7, which looks like the original solution to the solid red LED issue - I think WD Support helped the user restore the superblock from backup to fix the file system and allow it to be mounted, so I pushed on…
Good news is that I fixed my solid red LED issue by running through my second plan - the file system is restored and I can access all my files again, so all is well.
In case anyone is interested, I’ll document what I did a little later on. I’m just happy I resurrected it again!
