The models that are a crappy PC can, almost like any or other crappy PC. Some have a very tiny DOM that might or might not be enough for a recent system. Of course, once the system is minimally up, it can use the big disk for software. No idea if any have special weaseling on them, but you can always search for the model and e.g. Debian (that tends to have best hits). Running with read-only root or just initrd is also quite possible.
The ARM models tend to be very very very slow and small and have architectures that are obsoleted in many Linux distributions combined with hardware that's weird enough that NetBSD doesn't support it (e.g. LAN chip or SATA, which you might need in a NAS). And yes, looking at NetBSD pages and build configs is one avenue for finding well supported devices. Although the documentation isn't great or complete. Some models may also have weird boot sequences or rescue modes that are extra hassle.
The ARM models tend to be very very very slow and small and have architectures that are obsoleted in many Linux distributions combined with hardware that's weird enough that NetBSD doesn't support it (e.g. LAN chip or SATA, which you might need in a NAS). And yes, looking at NetBSD pages and build configs is one avenue for finding well supported devices. Although the documentation isn't great or complete. Some models may also have weird boot sequences or rescue modes that are extra hassle.
I keep wondering if a neat little buildroot config would work with some of these devices. Other odd options would be https://armbian.com/boards and https://openwrt.org/supported_devices .