Go back to basics. Do these one at a time, checking to see if it made a difference. Not that it boots and works, just see what it does differently.
Set aside the Unraid USB, don't connect it until the board acts normally.
Reset CMOS, test
Remove RAM, test, reinstall RAM, test
Unplug everything from the motherboard board except CPU, PSU, and front panel LED and switch connections. Yes, fans, mice keyboard, monitor, etc. Test
Start plugging things in one at a time, and test.
Hopefully things will start the work as you plug stuff back in, and obviously if just resetting the CMOS or reseating the RAM works you don't need to progress.
If the board doesn't give a bad RAM code when you have everything including the RAM unplugged, then it's got to be a bad PSU, CPU or motherboard, probably not the CPU.