With regards to the reboot even though REBOOT=ReallySuppress has been set: Setting REBOOT=ReallySuppress only prevents the app/update from forcing a reboot on the endpoint, it does not negate the need for a reboot. A 3010 exit code is still provided to ConfigMgr/Intune, and those tools will determine if or when a reboot occurs.
You can set the deployment in either ConfigMgr or Intune to show no notifications, and this should prevent the reboot notification from appearing on the endpoints.
You can set the deployment in either ConfigMgr or Intune to show no notifications, and this should prevent the reboot notification from appearing on the endpoints.