Laptop dGPU not working after MSHybrid to DIscrete mode Switches

Hello everyone,
I have a clevo pa70eg-g laptop. The laptop is 5years old. It has a iGPU with the Intel i7 8750h processor, running as intel UHD graphic 630 and a dGPU Nvidia geforce GTX 1070. A switch in the bios allows to switch from MSHybrid Mode to Discrete mode. Furthermore, the CMOS battery has drained out, forcing each reboot to set the BIOS default options, which would trigger this switch every time to set MShybrid from Discrete mode. Unfortunnatly after these repeated switches from MShybrid to discrete and vis versa, my Nvidia GPU is not working anymore, windows disables it on launch with error 43 displayed in the Device manager.

Sometimes after booting my computer GPU is randomly detected and starts to work totally perfectly. However, when the system is performing a iGPU to dGPU switch (due to the Nvidia Optimus technology), for example after closing a game using the dGPU, and returning to Chrome using iGPU to display video, the system crashes due to nvlddmkm drivers crash. Has anyone met this kind of problem ?
I suspect the chip responsible to the switch from iGPU to dGPU operations - ie PS8331BQFN60GTR-A2 - to be faulty but didn’t test it yet, moreover I do not understand fully the operations leading to the Optimus mechanism where can I found more info on it, and the hardware involved ?

Kind regards