Dell Optiplex 5090 SFF random shutdown while gaming

I have a Dell Optiplex 5090 SFF with warranty till Feb 2025. It has Core i5 11500, 32 GB RAM, RX 6400 Graphics Card. I am trying to play Flight Simulator 2020. Previously this game use to work fine. When am trying to play this game after long time now, the CPU temps are going in range of 85-95 deg. GPU - 85-90. After playing game for few minutes when I go to in game menu the system shutsdown. I have checked Windows event logger details but have not found any information. I have raised this to Dell support that my CPU temperatures are going really high. They have agreed to change the CPU cooler. I am not sure it's cooling problem or problem related to PSU.