So, I think I have a milder case of ADHD than most people do, and probably shouldn't have ever been put on medication for it. It mostly results in me being hyperfocused on activities I care about. With regards to keeping my focus on activities I dislike when my mind is wandering, I make very small, short term goals with timers, like if I'm writing a paper or academic journal article or something, I'll set very very short goals like "finish this paragraph and then I get 2 minutes of fuck around time." Almost like micro-task management to keep me going for a few minutes at a time all the time.