MacBook Air 2020 crashes when idle with external monitor

My MacBook Air 2020 frequently crashes (multiple times in a day) if left idle when plugged in to an external monitor. I have updated from Catalina to Big Sur but this has not solved the issue. I have also tried a safe mode boot, during which the issue did not seem to occur (though I am not sure the length of time required to be idle for crash to happen).

When I restart the device, I receive a notification and the following error message: intel CrashLog recorded due to unexpected reset

The external monitor is a DELL P2212H and I connecting to it via the USB-C port to a Fitfort Hub Pro which has an HDMI adapter. It works perfectly and I have no start up issues with the external monitor. The issue only occurs when I leave the laptop for a while when connected to the monitor - it does not occur without this connection.

Is there anything I can try in order to fix this?

Thanks