I disagree. And we can at least discuss whether a NAS that doesn't have ECC is that much of a NAS or not.
I'd take an old Xeon server with 64 GB of ECC memory, run its CPU in powersave mode, and slap TrueNAS (with ZFS) on it any day over buying a dedicated NAS.
YMMV but actual professional server gear, with ECC memory, is to me more of a NAS than a consumer NAS.
And nothing forces you to run a "full server": you can dedicate a real server to be only a NAS and slap the lowest consuming Xeon on it, which moreover you can run with a powersaving CPU governor.
Slap a 10 Gbit/s ethernet NIC in it and call it a day.
It shall be more reliable too.
You can of course cosplay with a consumer NAS but the real thing is better.
P.S: mine is a HP Z440 with a 14-cores Xeon (so a workstation, not a server: the advantage is that it's totally quiet)