disk errors after creating new volume which disappeared

My thunderbay 4 (16TB) is almost two years old. 4x4TB HDD.
I had 3 volumes on a RAID 0 (3Tb, 4TB, 4TB). All volumes were safeguard enabled.
When I went to create a 4th volume (1TB), it initially created it, but would not mount one of the 4TB volumes. In fact, that volume wasn't even showing up in SoftRAID. I unmounted all and shut down. When I powered the thunderbay back up, the new 1TB array was gone. The old 4TB volume reappeared but had a number of errors for the volume on one of the disks used to create it, with SoftRAID suggesting that the disk be replaced. I checked the log. The volume had a number of read errors. I tried clearing the errors and restarting. Upon shutting down and rebooting again, another disk showed errors as well, but just 1 error. I downloaded most recent version of SoftRAID and driver. I successfully verified the original disk with errors. I am in the process of verifying the second disk with errors.

I'm curious if this sounds like a corrupted directory or a failing disk (or two) and if there's anything to be done to be able to remount that volume that keeps not mounting and coming up with errors.

I do not own DiskWarrior. Am curious if it might resolve these issues. I don't use this RAID terribly often and am not in a mission critical stage of needing the data, but am curious if there's any obvious steps I could take. Am also interested in limiting cost so would rather purchase DiskWarrior than a new drive.