The way I see it, if you don’t like the noise from the HDDs you have two choices:
1.) Put the NAS someplace where you won’t hear it: closet, basement, under your kid’s bed, etc.
2.) Ditch hard drives and buy SSDs.
I’ve grown up around fans and electronic noise my entire life, mostly. It no longer phases me. I have my NAS units in my basement so no one else hears them but me when I am down there.
But if you buy all SSDs then you won’t get any noise. And it will be pretty fast but also it costs a pretty $$$.
Ah the choices we must make…