Nitro 5 AN517-51- Repasting, thermal pads and putty

Hello All,
I repasted my laptop's CPU/GPU as they were heating over 95C while gaming. Since it was my first time I managed to screw it up. Now looking for help...

I opened the laptop and unplugged the battery and removed the cooling solution and cleaned everything there. On the GPU and CPU used Thermal Grizzly and the pink paste, I replaced with Arctic MX4. Once I closed and put everything back together switched it on I was greeted by BSOD -'video scheduler internal error'.
https://www.acer.com/ac/en/GB/content/model/NH.Q9BEK.004
Automatically restarted and signed in to Win10. Tried to play a game to see if there is an improvement and was disappointed as I was getting colorful artifacts. Reinstalled the drivers and now the dGPU is no longer detected. The NVIDIA control panel doesn't open either.

In Bios, I see Intel iGPU. In management, I see this (Windows has stopped this device because it has reported problems. (Code 43))

I have ordered a new paste and thermal pads(1mm) from Thermal Grizzly and will try to re-clean everything and repaste. Have I chosen the correct thickness?

Do you think I have damaged the GPU? Please advise if I can do something differently.

Many thanks!