A follow up question regarding filesystem. The disk volume was xfs (zyxel also calls it jbod) earlier
JBOD is not a filesystem, it's a RAID flavor. The partition contains a RAID array, which contains an xfs filesystem.
and now it is NTFS. Does this cause data recovery problems?
No. The fact that it now has a different, empty, file system has caused the data loss. But it doesn't cause recovery problems.
Should I convert the partition back to xfs and rerun the data recovery?
NO! Putting a new filesystem on a not empty disk is like putting a new random street map on an existing city. Most buildings are still there, others aren't, because someone has put a new street over it. And you can't find a particular building, because street names and numbering are different.
Putting just another random street map over the same city doesn't solve that problem. It actually worsens it, because now other buildings are trashed, without repairing the previous.