I may have ADHD, I never went for a diagnosis and found body doubling useful at times, especially when I was in school some decades ago, back then I had no name for it. However, I find white noise very helpful with staying on the task and with increased focus. My company moved, about a year ago, into a very cramped office that is also extremely noisy. This exasperated me, I would get drained of energy in a couple of hours and my focus was being severy affected. I even considered quitting and looking for something else. As a last resort I started listening to white noise. I’ve been using white noise (white+brown+pink) for about a year now and find that it helps not only with cancelling out the noise but with focus and staying on task in general. I even use it at home at times. I know this may not be useful for everybody but I’m sure it could help out some of you. I use https://noises.online/ and mix all the types of white noise at the same time for maximim coverage but any type of white noise generator would do. To me it feels like being close to a waterfall. At first my ears hurt a bit after a few hours of white noise but got used to it after a while.