I was given a tour of a commercial BBQ kitchen.
Several hundred pounds of meat on trays that rotated slowly over 18 hours in a natural gas low heat oven. The only smoke was from small compartment with a couple of hickory split logs in it.
This kind of operation could not offend neighbors. There was hardly any being emitted.
The concentration of restaurants along Austin’s 6th street, using backyard smoker technology, must be awful thick smoke.
The method of cooking the Que is most of the source of the problem but
many will argue it is the basis of the BBQ taste. But as you pointed out
the heat generation could be from a different source other than wood.