I can't really fahom any use case where a typical home NAS would benefit from ECC memory. These things come with 1-8 GB of RAM and read and write files. At worst they transcode files.
How do I put this?
The chace that an error (that would otherwise be corrected by simple ECC DIMMs) will irretrievably destroy your files, is super duper low. Especially compared to human error or software bugs. And if your files are really that important, you need a proper backup anyway.
And if you have a proper backup, then even the most unlikely unfortunate chain of of-by-one errors shouldn't matter.
Like, get ECC, if you want. But… "useless"?
Also: I belive the Pi5 features some sort of on-die ECC.
I once got myself a small projector. It ran on Android. I didn't want to connect it to my network. Unfortunately, an unsecured Wi-Fi hotspot would sometimes pop up nearby, which the damn thing would connect to in order to download ads and bother me with nonsense.
The workaround was to give it Wi-Fi, but block the internet connection in the router. The solution was to throw it away. Malicious little fuck.