A proper HVAC system goes a long way.

But just like with “non smoking sections” back in the day: It still reeks to non-smokers. People vastly underestimate just how much even being a “casual smoker” does to your sense of smell and tolerance for tobacco stank and so forth. And the people who actually are going to cigar lounges, regardless of what they tell themselves, are a few notches past “casual” and so forth.

Which gets back to the issue and why most bar owners aren’t actually fighting for indoor smoking to come back. Running the gauntlet of chimneys outside the door? it sucks, but people will do it to hang out with their friends or go out with the really cute Romanian girl. Sitting in even a light haze of smoke for a few hours? Fuck that noise, let’s go to the bar across the street.

Which gets back to the cannabis bar problem. You are basically only catering to people who smoke at that point, and that is a much smaller population. And that also ignores the issue with contact highs and even delayed reactions triggering a shitshow of DUIs.