OP, RAID is NOT a backup! Your recent data loss is not a valid reason for getting a NAS with RAID. Depending on how the RAID is configured, the biggest benefits are uptime and performance. RAID adds complexity, which works against your desire. Also, it does nothing to protect you against malware or accidental deletions.
This. There is nothing wrong with a NAS device that uses RAID, but it is not a backup system.
A backup system protects against accidental or malicious changes to your data.
RAID will happily clone all of those changes to the second drive as it's happening.
RAID is about availability (data is still accessible if a disk fails) rather than protecting against the loss of your data.
With more complex tiers of RAID than RAID1 (mirroring) such as RAID5, when a single disk fails, you often find that you can lose the entire array during the rebuild process, as the intensive rebuild process can cause another of the drives to fail - especially if they are the same age.
NAS alone is not a backup but a NAS that is running in RAID mode does offer some redundancy. Good enough for media in my book. I still have all the discs if something really bad happens.
I would generally suggest keeping backups of small disc formats such as CD and DVD, while worrying less about Blu-ray/UHD discs.
The cost to have a backup for that media is less than the time it would take to re-rip hundreds of discs.
It's generally a lot less storage to keep backed up too, since the largest a CD can be is 700MB, and ~7GB for DVDs.