Raspberry Pi holds its own against low-cost ARM NAS, and the Youtube version. I'm running a Pi4 in my garage as a backup but just using a couple external hard drives with USB3 connections. Also encrypting everything on the two drives so a power outage does require a bit of me logging in and re-mounting the drives (though I also have a small UPS on it and I'm pretty sure that lasts for a couple hours when the drives are in stand-by mode).