Steam starting on windows boot can brick your system if you have AMD iGPU enabled

Had to reset my CMOS due to an issue with my onboard NIC, and ended up unable to boot into Windows (would actually get to desktop but then nothing worked). After a bunch of troubleshooting in safe mode, re-flashing my BIOS multiple times, uninstalling/reinstalling drivers, checking going through Google/Reddit etc for about an hour I decided to just nuke my install since I have all my userdata on a separate drive anyway. But the issue just returned once I was done setting everything up again.

Turns out it was Steam:

https://steamcommunity.com/groups/SteamClientBeta/discussions/0/7599331177366620489/

Fix is simple, either disable start with windows by booting into safe mode or disable the iGPU again.

Kinda big issue to go unpatched for this long, wonder if it only affects certain CPUs since the few people that commented with their specs all have a 7800X3D (same as me).