I was a dummy and swapped all cables on my new PSU except the SATA drives. All three drives no longer show in BIOS. They are shucked Western Digital Easy Drives. After some research, it seems it could be the fuses, the diodes, or I might just be screwed. Interestingly, all three HDDs provided different readings from the multimeter, which confuses my next step further. I've attached pictures with the readings. I hope somebody could provide further guidance.