I have a very similar story with a Netgear ReadyNAS nv+ that has been running for about 10 years. I put 4x 2TB disks into it on RAID 5, and have a spare sitting

I have a very similar story with a Netgear ReadyNAS nv+ that has been running for about 10 years. I put 4x 2TB disks into it on RAID 5, and have a spare sitting in a box in case I get a failure. Daily offsite backup. Not a single issue over the years. I have ssh, and it's just Debian under the hood, so I've added a bunch of extra stuff to it. I have no idea what I'd use nowadays. As someone pointed out, if the box itself dies, I'm screwed. I think it uses mdadm under the hood, but that's a guess. Maybe I'd just buy a mini ITX barebones that holds 4 drives, boot off a usb stick that runs FreeNAS and configure the disks in a simple 2x2 mirror.