Juul was always a scapegoat. They are nothing other vapes aren't; they were just popular at the wrong time and took the brunt of America's ridiculous attitude to vaping
Banning flavors was the most effective move to deter kids from vaping JUUL. They all use the gas station disposables now.
When I was an underage smoker, advertising did nothing to affect my purchase. It was all about access. If they really want to address underage vaping, they need to crack down on places that sell to minors, just as they did with cigarettes.