Question PC Keeps Turning Off! Tried Everything!

[Sorrybut you need to change your username.]

I upgraded my PC from:

1. Ryzen 2200G to Ryzen 5700X
2. Added a new RTX 3060
3. Upgraded the PSU from 400W Cooler Master to 550W Cooler Master
4. Added another 8GB RAM stick of 2666MHz (frequency same as another 8GB RAM Stick I have)

For some reason, my PC keeps turning off completely randomly. It doesn't restart, just turns off. All temperatures are normal.

I had used a different 500W PSU initially which wasn't rated. I thought that was the issue. However, changing it did nothing. Ran some diagnostics on RAM, didn't show anything up. Updated the BIOS (Asrock A320M-HDV v4.0), still the same issue.

It doesn't even last a few seconds on OCCT. However, I noticed a spike in voltages of CPU and GPU with OCCT right before the crash:

 

[rgd1101]

model of this 550w cooler master?