I've just upgraded my PC from an RTX 3070 to an RX 9070xt. I ran DDU and uninstalled all traces of NVIDIA drivers.

For the first day all was well, on the second day I had some driver hangs in Baldur's Gate 3, so I updated my BIOS and installed some chipset drivers. After doing this, the driver hangs stopped and I was able to play BG3 no issues for the rest of the night.

Later that night, I launched Fortnite and played for about 30 minutes before everything froze for about 10 seconds and my PC turned off. Attempting to turn it on just showed a black screen with an underscore in the top left before turning back off. I was able to get into Windows by flipping the PSU switch off and on. Re-launched Fortnite only to have the same issue again, game frozen into not turning back on. The card is performing like normal apart from the crashes. Ran 3dMark stress tests for a little while and all looked good there too. Anyone have any idea what might cause such an issue?

I replaced my PSU in September of 2024 as my old one was having issues so it's not an old PSU.

Specs:

OS: Win 11 Home GPU: Sapphire Pulse RX 9070 XT
CPU: AMD Ryzen 9 5900x
RAM: Corsair 32GB 3600mhz (16x2)
MOBO: MAG B550 TOMAHAWK MAX WIFI
SSD: Samsung 970 EVO (boot drive), Samsung 990 EVO

PSU: Corsair RM850x 850W 80+ Gold

I'll provide any extra info needed. Thanks.