I have a hp server rack, with 6sas 4tb hdd and 2 sata 800gb ssd (for boot drive only) The main noise maker are clearly the HDD, at least I know when a linux iso is being download from my arr suite! But the HDD don’t make noise 24/7, just sometimes when there is a lot of write.
I’d recommend using a ssd as a cache for the spinnin rust, and another ssd for the boot drive of your OS (I use proxmox btw)