dj_reed

If you want good and fast in implement thermal paste you can use Ceramique 2, but I think the most efficent for standard use are the MX-2 and MX-4. For extreme efficiency you can use metal thermal compound like Conductonaut :-)

Check copper - maybe it failed. Sometimes high temperatures occurs when the gas inside copper pipes runs away.

IPA should be good with brush.

Firstly disable your GPU in device manager. In some cards you have to do it before nvflash running.

Maybe your cooper cooler failed? I had one notebook (MSI) in which one the GPU cooler (cooper) failed - the temps was unnormally high and going from 30 degs to 80 degs in damn 10 secs.... after replacement everything started working.

Is it support undervolting?

Great job!!!