But to add to this, I feel like there are different kinds of addictive behaviors at play that are more susceptible to one medication or the other and are based on different systems.
For instance, the food-craving reduction in GLP-1 is almost certainly not just related to reward and goal-seeking behavior. It literally affects hormone signaling for satiety, and slows down the movement of food through the stomach, and affects, globally in the body, responses to metabolic signals. And it probably has a global effect on the way every cell in the body works, which might be why there are positive health effects beyond just the weight loss.
ADHD medication, on the other hand, targets the goal-directed activity system directly. It seems much more likely to me that reduced appetite is just as much driven by the focus and "let's get shit done" mode that is artificially increased with dopamine. Both result in reduced eating but through massively different pathways. Basically, you pay attention to the biggest wave in the pond (the waves in the pond being a metaphor for all the things your brain COULD pay attention to). So when the goal-stuff gets increased in size, the food-seeking is automatically smaller by comparison, and less likely to drive your behavior and thinking.
I don't think I can say that there is much of a pattern between ADHD and overeating, just based on how easily I can predict if someone is overeating or not if I know they have ADHD. That is, it would be a coin toss.
The simplistic answer would be: Semaglutide reduces addictive behavior if it's driven by emotional regulation needs, and ADHD medication reduces pure drug-like craving. As seen in studies where people that start lisdexamfetamine (ADHD medication common in the EU) have a huge reduction in actual amphetamine abuse.
Case in point: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/... Findings In this Swedish nationwide cohort study of 13 965 individuals, lisdexamphetamine was significantly associated with a decrease in risk of hospitalization due to substance use disorder, any hospitalization or death, and all-cause mortality.