Seems like not a Bricked issue for me but a dead card.
If its not totally detected by your motherboard bios and your OS then its time to RMA it.
This is what I'm thinking as well. I mean the whole card worked fine for a while even after flashing it. It's just when I changed the PSU and added another card (same model) that it died.
I've also gone through the motherboard BIOS on two different computers and haven't been able to see my GPU anywhere.