Many NAS work like that though. Hardware RAID always seems to work like that so if you get a fancy card that supports RAID you been make sure you have a good long term support contract that will be there for you when there are problems (if you are not paying hundreds of thousands per year you don’t have a good support contract)
Not all are that way. Many run ZFS which is great for this and you can replace broken hardware and recover. BTFS is commonly used as well, probably not as good as zfs but likely good enough.







NAS can be two different things.
NAS is just “network attached storage”: a computer that has a bunch of disks attached to your network. IF you put a single disk on your network and nfs/samba to share it you have created a simple NAS - I strongly recommend you put in more drives for redundancy, but that is all NAS is.
Often NAS is taken to mean not just the above, but a custom machine that does the above. The downside is these custom machines are often slow, and put weird hardware/software on them such that if the whole box breaks (as opposed to just a single disk failing which they are good at handling) you may not be able to recover anything. One variation of this you want more space and discover you can’t upgrade it at all. They are an easy way into NAS, but the downsides are such that I can’t recommend them anyway.