TXRon is correct. I had the same problem and posted about it a couple of years back. I had to open up the box and blow out the dust. It was matted on the board and chips like a rug. Not an exceptionally easy process but doable. Very small screws and I think Nvidia has a tutorial on the process. So I disconnected everything, bought a little blower for doing circuit boards and it has little brushes and attachments to focus the airflow. Got it from Amazon. Was about $25 Canadian. Fixed it right up. I had a square of white cloth to lay it on and a little container to put the screws in so I wouldn’t lose them or accidentally blow them away. It was like a brand new 2019 Shield pro after I did that and put it back together. I will see if I can find the instructions. Here is a good thread.
Lots of you tube vids.