Been using unRAID for quite a few years now, and I am very happy with it. I've currently got 12 drives in it, with space for a couple more. I have two of them set as parity drives, so there's some redundant safety net. That'll keep it going if a drive or two die, and will only lose data if a third happens to die at the same time. Of course it is not the same as having multiple backups, I am aware. But it is enough of a safety net for my not-really-worth-anything file backups at home. I like how it only powers up drives that are in use, versus having to have all drives in the array running at the same time. And the fact that they're actually just solo drives you can individually pop into any machine and read its contents, versus having to have a fully functioning array to read conventional RAID drives. Which basically means if I *did* actually have a third drive fail all at once I would still be able to read the fully intact files that exist on all the drives that did not fail. If that happened it wouldn't suck as bad as a conventional RAID setup having a similar failure, as the entirety would be basically useless.
unRAID isn't perfect, but it works very well for a home gamer NAS setup. At least, it does everything I want it to do, and I like the way it does it. When I have had drives die over the years it is quite nice to just pop in a new one and continue on as if nothing happened. That part isn't unique to unRAID, exactly, but I like how it does everything, including how it does that.
It's built with leftover hardware from one of my gaming PCs from many, many years ago. AMD Phenom II X4 965, a very old quad-core CPU, with just 8 GB of DDR2 RAM, most of which is just disk cache. I think it only ever uses about 1/3 of that for non-cache usage. An old ADATA 480 GB SATA SSD as a cache drive sitting in front of the platter array to speed things up a bit. And the 12 platter drives behind that, connected to the motherboard SATA and an SAS9211-8I 8PORT Int 6GB Sata+sas Pcie 2.0 controller. I imagine there are cheaper/better controllers around these days, too. Looks like I threw that together back at the end of 2017, and it is still going. If anything major dies, another nice thing is unRAID just boots off a USB thumb drive. All the drives could simply be moved to a new motherboard and controller without having to do anything else besides swap everything over and plug that thumb drive into it and boot. It doesn't seem to want to die on me yet, though, haha. I may swap to something newer that's dirt cheap just to gain some efficiency one day, but I have sort of just been waiting for something to die before doing so. And so far, other than an old drive every now and then, it just keeps running.
Oh, that's another thing. Your drives can be any capacity, and if an old 2 TB drive finally bites the dust you can swap in a new 10 TB or whatever, and just use it. The only limitation is that your data drives need to be the same size or smaller than your parity drives. In a pinch you could use a data drive that is larger, but it will limit its usable size to the size of parity, so at some point you'd also want to upgrade your parity drives accordingly. You're not limited to the smallest drive in the array like conventional RAID.