Samsung QE75Q900RAT Freezing Issue: Suspected Graphics Processor or Main Board

Samsung TV model QE75Q900RAT
Main BN41-02679B

Hello repair friends
the customer entrusted me with this TV for repair.
When cold, the TV starts, no communication problem between the ONECONNECT box and the TV. After 1 to 2 minutes, the image freezes, no more interaction with the remote control and the image changes color, then the TV stops.
The ONECONNECT makes "clicks" but the TV does not start.
It does not want to restart, you have to wait a few minutes to reproduce the sequence.
I tried the ONECONNECT and the cable on another TV, they seem to work well.
I suspect a graphics processor problem. Do you have any ideas for my research?
If you have a BN41-02679B card, I could also be a buyer.
Thank you all, and happy holidays.

The album itself is available here, for example: http://rtv-oborniki.com/plyta,MXK8.html

Thank you my friend, I think that indeed, I will move towards a card replacement.