Curiously, my Fedora Linux Live USB is working just fine. It boots and everything. Didn't try to mount the NTFS partition on the SSD though. And it doesn't have drivers for the wifi, maybe cause it's an old version of the linux live distro I just had lying around. So, I couldn't test everything. But at least there's no problem with the RAM.
The error I get in the BSOD is SYSTEM_THREAD_EXCEPTION_NOT_HANDLED in Ntfs.sys.
I feel that's not a lot of information to go on.
But we were not out of the woods yet... When we got to the step where you need to connect to a wifi network it didn't show any. Turns out it didn't have any drivers for the wifi card. That took some manual searching in the Microsoft update catalog:
I honestly did not expect the Windows 11 installer to BSOD when running from a USB. I'm not sure what to do now.