1. Newer DAS devices connect using USB-C, but USB type-A/e-SATA ones can be found.
Edit: figuring out how to run TrueNAS as a guest OS was a nightmare, the first 5+ page of results will be about TrueNAS as a host.
I also want to set up a NAS on a mini-PC with some sort of attached external storage, but I haven't been able to get past this blocker. USB is the only external interface these mini PCs typically support.
Similarly, heres a very low power writeup I did for using 2.5" drives with a dedicated power hub/splitter. http://www.jofla.net/?p=00000106#00000106 This will still have issues if the mains lines sag (a pole goes down somewhere), but you can fix it with a reboot remotely. Other than that it works great.
This was/is definitely a labor of love, primarily as I've come from a time when all you could get for a server were huge boxes idling at 50 watts, so i felt guilty of all the power I used to consume.
You're right, and I don't recommend USB as the only backup solution. I an old eSATA enclosure - not sure if that's an improvement over plain USB - as a secondary backup and keep the device on long enough to complete)
You could also buy a PCIe to multiport SATA (RAID) card, but you'll also need a bigger[1] NAS-like case[2] to house the hard drives and multiple power cables for the drives
1. Depending on how mini your PC is and how many drives you want to attach to it
2. I have noticed any case that's sufficiently NAS-like (hotswap trays) is sold at a premium.
The PC's PSU will need SATA power on its cables or else you'll need to scavenge a separate PSU and use the paper clip trick (or better yet, a purpose built connector) to get it to power things on without a motherboard connected.
Once you have all of that, then it's just a matter of housing the disks. People have done this with everything from threaded rod and plastidip to 3D printed disk racks to used enterprise JBOD enclosures (Just a Bunch Of Disks, no joke).
Total cost for this setup, excluding the disks, can easily be done for less than $200 if you're patient and look for local deals, like a Craiglist post for a bunch of old server hardware that says "free, just come haul it away".
Check or r/DataHoarder on reddit or ServeTheHome's blog
https://www.reddit.com/r/intelnuc/comments/ibchlz/nuc_m2_sat...
If it was just one, I'd put it down to random bad luck. But with that many failures I assume they are doing something stupid/cheap.
Usually they would simply fail to power on but sometimes individual slots seemed to die (which RAID just loooooves).
And having an entire enclosure fail and waiting days/weeks for a replacement sucks as you lose access to all your data.
I eventually bought a Jonsbo N3 off of Aliexpress and PCI SATA card (to support more than the 2-4 drives most motherboards support) and that has been working well for months.
The Jonsbo N3 is not comparable. I own one as well (how quiet is yours? I upgraded the rear fan but my CPU fan is noisy), but it's a complete PC case, not an external HDD array.
There is one deeply troubling flaw to them though, they don't turn back on of the power goes out, until you physically hit the button again. I think this is alas all to common for many of these enclosures!