When I quit smoking (and then, much easier, vapes), I found that my brain wasn't working any more. I could sit and watch the sun cross the sky and then go back to bed and my bipolar up/down had become zero/down. I had not felt this bad since I was 17 years old ... when I started smoking. I gave it 3 months to make sure I was making a logical (not addicted) decision and then took up vaping properly and my brain activity was back.
Nothing that has that big an effect on the brain can be non-addictive - that's just how addiction works. However, over Christmas I got food poisoning and just could not face the texture of flavor of vapes and so I didn't for 3 days. Never wanted to, not even the urge. When I was feeling better, I took it up again just as a rational decision without any cravings or intense relief when I did. Compared to the attempts at smoking while coughing and hacking which led to my quitting smoking, the addiction was undetectable.
So, I'd say (like many vaping studies) that the addiction is at least 95% less in that it must be there but I couldn't detect it.