This was posted at 2:39 AM American Central Time.
Modded bios to allow m.2 nvme boot function isn't the issue.
To be honest, you'll likely need to breadboard the pc. That means unplug everything except cpu, cooler, 1 stick of ram in 2nd slot and 2 power cables. Absolutely nothing else plugged in. Then try to boot.
All you are looking for is the pc posting and staying on. If it still fails, swap out the ram stick. If it still fails, change the slot the stick is in to B1. If it still fails, then either the motherboard, cpu or psu is toast.
If it passes, start plugging stuff back in, starting with the ram. 1 stick at a time. Keep plugging/rebooting until it fails. Only plug One component in between boots. Leave the drives for absolute last, no point in suffering OS startup.