if noise is your primary concern, don’t pick exos or the WD DC HC series, they’re data center/enterprise hard drives and those guys don’t care about noisy drives or heat and they use crazy loud fans so you wouldn’t hear the drives anyway.
your 12tb is 5400rpm, when you go bigger they start using 7200rpm drives and they’re typically louder but not always. 5400rpm is usually quieter and cooler running.
on my mobo and cpu, I use the hba first as theres more bandwidth. mobo sata last as one of my two nvme ports runs through chipset and chipset to cpu is limited bandwidth, roughly 4GB/s total so sata and one nvme competes for that.
if you have a cpu/mobo thats made in the last year or two you would have more speed for that interconnect and its not that big of a worry.
TP-link wifi plugs with energy monitoring (theres a 4pack on sale right now too) and theres a github repo for a energy monitoring docker and also one for grafana that pulls from these tp-link smart plugs.
I put the server and drives in another room so I don’t hear it. but all the larger drives are 7200rpm so they are a bit noisier than some of the “smaller” 12tb and 14tb drives.