While not DIY, I would like to also call out an interesting discovery lately.
https://www.ugreen.com/blogs/news/ugreen-makes-strategic-ent...
UGREEN has apparently inked deals to drop their DXP2800s into (some) Walmarts, which also included bringing in some 10/12TB Toshiba N300 Pro drives as well to go with them on the shelves. Being a super-rural American, I was a bit surprised to see this on my local shelf as a nearly turnkey solution in an area where there's nothing remotely close to a Best Buy, even.
Even more surprisingly: they've been sold by Walmart below minimum advertised prices at UGREEN a few times normally...
One thing to be aware of is that many (all?) current UGREEN boxes can't support ECC RAM. For anyone looking to use ZFS like the article linked here, that may be an issue, depending on one's view of the debate about whether ECC is necessary with ZFS.
I had one of the DXP4800 Plus NASes for about a month before RMAing it.
The CPU would immediately hit 100C with even the slightest whiff of load.
The entire thing was also unstable and would regularly just lock up without any kernel panic or other error message available, could even get kdump to gather anything (I'd binned their dodgy NAS OS and installed Debian).
It also seemed to amplify the noise of the hard drives within. Every thunk of a drive head moving around would be audible from a different room. Not sure how they managed to do that, but it's an acoustic nightmare.