We need to differentiate between grilling a BBQ. They’re two different things!
Barbecue is using indirect heat to slowly cook things. It can be done using a grill, but not a propane one! It’s usually using wood chips to smoke the meat while slow cooking it.
Grilling is putting the food directly above the heat source and cooking it relatively quickly.
What most people here refer to as BBQ is not really BBQ! It’s just grilling.