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.

Then you should have not bought it

Not the parent comment, but we should be aware and shouldn’t be naive.

I am assuming that you had enough saved up in the bank hence you were happy about the impromptu 2 years vacation with severance granted to you?

When it does snap usually the steel and concrete remain intact. It’s the stem of the bridge that’s most vulnerable to shear or buckling forces… at least that’s how my stuff fail.