I’m leaning toward a short somewhere, since you said the PSU starts up with the paperclip but not when plugged in to the board.

As a renter, I don’t pity the mere $200 increase you’re dealing with.

Someone opened the soap dispensers and put doodoo in them.

I actually found an A to A cable in my Big Box of Cables I Might Need One Day™ when trying to flash my Gotek floppy emulator with FlashFloppy firmware.

Rim that fucking anus.