Check what changes in lspci
command between not having the GPU connected vs. Having it connected.
I am suspecting that your PCI-E bandwidth is getting exhausted once the kernel activates your GPU.
Edit: Although I could be wrong about this. So makes sense to try passing “nomodeset” to your kernel parameters and see if that changes anything.
It’s tough when people like us sit here online and bicker at people for not doing their jobs… when we can see they are literally overwhelmed by an avalanche of attack from rightwing douchebags who have infinite resources and infinite bootlickers to mindlessly repeat propaganda.