PC crashes under load (black screen + sometimes full shutdown in games)

In Call of Duty: Warzone my PC crashes under heavy load.

Symptoms:

• Screen goes black
• GPU fans ramp to 100%
• Sometimes system freezes
• Sometimes it fully shuts off like a power cut

Temps are normal and nothing is overheating.

I reduced GPU settings:

• 1800 MHz
• 950 mV
• -10% power limit
• 120 FPS cap

This reduced crashes a lot and I can play longer, but it still happens randomly.

Specs:

• Ryzen 9 7900X
• RX 7900 XTX
• 32GB DDR5
• 850W GameMax GMXPRG PSU

Looking for help identifying what could be causing this.