Question Updated Bios via mFlash, PC now wont POST and has white CPU debug light

[JakeStanden]

See title. My was working fine for years, but had some weird lag issue with during wake from sleep that led to it rebooting. Read on another thread this could be a bios issue, so I updated the bios via mFlash as intended. The process worked correctly and concluded as intended, but now nothing works. No display output, no lights on the RGB Ram or GPU, only the case fans and GPU/CPU fans spin, and the mobo has a single white light on the Debug LED under CPU.
Thing's I've already tried:

1. Install an older bios file via the mobo sub flashback button; this completed successfully and rebooted but no change
2. Clear CMOS; did this, no change
3. Try an HDMI cord instead of DP, no change

I haven't touched any hardware, PC worked great beforehand, but now its bricked and I can't do anything to get it to POST or change behavior. What do I do now?

Specs:
AMD Ryzen 5 5600X 3.7 GHz 6-Core Processor
MSI MPG B550 GAMING PLUS ATX AM4 Motherboard
Corsair Vengeance RGB Pro 32 GB (2 x 16 GB) DDR4-3600 CL18 Memory
Samsung 860 Evo 500 GB 2.5" Solid State Drive
Samsung 970 Evo 1 TB M.2-2280 PCIe 3.0 X4 NVME Solid State Drive
NVIDIA Founders Edition GeForce RTX 3080 10GB 10 GB Video Card
EVGA 700 GD 700 W 80+ Gold Certified ATX Power Supply
Microsoft Windows 11

 

[Lutfij]

Welcome to the forums, newcomer!

Try and reseat the CPU and see if the issue persists. How old is the PSU in your build?

 

[JakeStanden]

Welcome to the forums, newcomer!

Try and reseat the CPU and see if the issue persists. How old is the PSU in your build?

It is as old as the rest of the build; that is to say, about 2.5 years old. Would altering bios have done anything to the PSU?