MCU shutdown; timer too close

Hello, I have a super reliable v-core 3.1 but it's started having errors mid print. Not every print fails, but has been once a day for the last four days. The error message has been the same and is attached. I have not made any software updates to the machine. The controller is a RPi 3b. No fan or heatsink on the RPi We've had a heatwave with temps up to 108°F and the printer is in the unconditioned garage so I suspect that the CPU may be getting too hot, derating, and then the fault gets thrown. What does the community think here? Is the CPU overheating most likely the cause? How to solve? Should I add a cooling fan to move air across the RPi? Should I get a RPi 4 or 5? I'd rather pay a few bucks more to never see that message again.