computer restarts with message " Your computer was restarted because of a problem"

The latest macOS versions are having various issues with automatic computer sleep mode.

Some systems crash and force a restart, others freeze up and are unresponsive.

As a test:

Turn on "Prevent automatic sleeping when display is off" and only allow the display to turn off.

Then just leave the Mac on with the display off and shut down for longer periods of non-use.

You're welcome.

Let us know if preventing sleep helps or not...

Sadly if one of the drives that makes up Fusion drive is failing, then that drive could be causing a problem.

I might try running first aid on the Fusion drive, to see if that helps.

see > Repair a storage device in Disk Utility on Mac - Apple Support

And/or Erasing the Fusion drive, to see if that helps.

see > Use Disk Utility to erase an Intel-based Mac - Apple Support

You're welcome. Hopefully "Prevent automatic sleeping when the display is off" helps.