Just an update. Bought a QNAP TS-216G, seemed to be on backorder EVERYWHERE, but then somehow found it in stock at Newegg. A little higher price, but available to ship asap. I also bought a Crucial MX500 4TB SATA SSD to put in the NAS. I might just go with 1 drive for now and see how much data my kids and wife actually have to back up. For me, I care about all OneDrive files and folders, but for the kids and wife, I really only care about their photos and videos. They are each using Google Photos and OneDrive for automatic photo backup, so the media exists in 3 places including their phones. Adding a physical backup on a NAS seems like the next logical thing to have as a just-in-case. Really it's because I'm a tech nerd and just want a NAS and this is my excuse to do it. Ultimately, all photos and videos will be in 4 places, including 2 physical (phone and NAS) and two cloud providers.