I see. Did you try a bios flash using the back side of the board w/ a USB? Sometimes you can do that even without a display signal. The other thing I would try (if available) is use another harddisk and not use the one which remembers the Intel ME firmware installed. I am hoping between a fresh bios install and a new hard disk you might be able to at least get it to boot.
If the power is not coming on at all then I don't know what is wrong as that doesn't seem to be related to the PSU or anything else.
Also maybe this helps? https://rog.asus.com/forum/showthrea...Intel-ME-(Z490
) or https://www.asus.com/support/FAQ/1038878/