I have not tried to recover data from a nas device with a software before since i have not experienced this, lets see if another user can share some ideas and tips on this matter.
A system only restore leaves the data and share in tack. A quick restore deletes the data but doesn’t over write it so recover may be possiable. A full restore over writes the data multiple time so no data recovery is possiable
There are utilities that may help with this but I don’t have any details but a search on this forum for recovering files should help.
you should always have a backup for any computer / drive however i assume this is not the case here. it is also advisable to keep a copy off site too for disaster/fire/theft…