Pc screen turns off while gaming

Hey, i receintly upgraded my rx 7600 to a rx 6800xt to switch to 1440p, i bought it used for 220usd, After that in some games under stress i think the pc screen just turned off but the pc kept running which i had to restart then, and the sound stuttered while the screen turned off.

it crashed while playing at 1440p i played dead by daylight. i checked task manager it was indeed the rx 6800xt with 16gb vram and it runs some games like perfekt(roblox)

maybe psu is to bad or other specs the problem?

Specs:

Rx 6800xt Aorus Master

Motherboard: Prime B450M A2

Cpu: ryzen 7 5700x

ram: 32gb ddr4 (2x Vengeance(16gb) 1x crucial(16gb)

aio 360mm yeyian

psu:750watt coolermaster Gold 80+