RAID is not backup. RAID is used for increased capacity, throughput or uptime. (Depending on configuration)
Multiple volumes would likely get corrupted just as much with faulty RAM as RAID would. Besides RAM there’s controller, CPU, power supply and possibly more single points of failure in that NAS, that would destroy both RAID and multiple volumes.
So assuming you have external backup, I’d go with RAID for better uptime as opposed to some custom multi volume pseudo-RAID for the same.