Anecdata, but still:

I ordered a Xyber NAS (N150) back when they were still in stock, wiped the Ubuntu that came with it and built up a NixOS config [1]. The power usage is very good (12W with 2 internal SSDs, bluetooth, wifi and a bunch of services running).

If it dies, I won't be too sad since it was about $210. But it's doing pretty well (24/7) so far.

[1]: This ended up being useful. The built-in eMMC chip that I had installed the OS on gave out after ~1 month of usage and I had to reinstall. Thanks to the NixOS config, it took me much less time.