Why is my PC shutting down with PBO Fmax Enhancer enabled?

I'm having issues with my PC shutting down unexpectedly, especially during gaming. Here are my specs: I have a Crosshair VIII Dark Hero motherboard, an AMD 5950x CPU, and an RTX 5080 GPU. My RAM is 64GB of G.Skill DDR4 running at 4000MHz. I'm using a new ROG 1000W Platinum PSU, and my system has a full custom loop for cooling. The problem started when Battlefield 6 launched; I encountered random shutdowns during gameplay. I adjusted some BIOS settings and it seemed to stabilize things, but I can't remember exactly what I changed—most settings are now on auto. Initially, everything worked fine for 2-3 years! Last week, after upgrading to the RTX 5080 and running a Firestrike Extreme Benchmark, the system shut down before I could even see any results. After some research and recommendations, I replaced the PSU, but the issue persisted. Upon investigating the BIOS, I suspect that the PBO Fmax Enhancer might be the culprit. When I disabled it, the benchmark ran successfully and I didn't experience any shutdowns. I'm baffled because I used that setting for years without issues. Could this problem be due to hardware degradation? I can still achieve a stable all-core overclock at 4.6GHz and 250W without problems. Any insights would be appreciated!