Yeah, it’s fine … wait, IronWolves in a living space? Paired with that acoustic desk it must be like a train yard, but with more vibrations :D.

Edit: wrote this before I saw your comment acknowledging the same.
Well, with HDD there is the noise of the drive itself (the constant one & the searches, spin-ups), and the vibrations which can get acoustically amplified. For the former you need a case, any case, maybe a case in a case (ventilated ofc), for the latter I’ve always (since late 90s) had my HDD on full rubber, no non-rubber connection to the case.

My current NASies all use these (in desktop cases, I don’t like server hardware if it isn’t necessary, like with disks):

(They cost like 2 monies with shipping.)

So if going the 3D-print way, as you mentioned, I would def add the suggestion of incorporating thicc rubber pads or rubber straps into your design, like these ones (I’ve used them a lot decades ago, the only commercial option for silent PC enthusiasts at the time, but I’ve built then myself too):

(It’s rigid, the disks won’t fall out.)