I also think ADHD is a combo of many different, more specific problems that we blob into ADHD since we are not precise enough to diagnose it beyond the 3 types we have now, and these sets of problems are responsive to stimulants.
For some people with ADHD, this will work very well, others will not. Some with ADHD are already naturals at mindfulness because they have really bad time blindness. They are always, a bit too in the moment and low anxiety.
> ...naturals at mindfulness because they have really bad time blindness...
FWIW, this is not what "mindfulness" means. Mindfulness is a combination of concentration (i.e. intentionally focused attention) and insight (i.e. a deep intuitive knowledge and familiarity with the three characteristics, viz. anicca, dukkha, anatta). People who have reached the deepest stage of enlightenment (known as arahants) are believed to be able to switch their default mode network on or off pretty much arbitrarily (there is interest in verifying this claim experimentally, and it doesn't seem to have been outright refuted so far); they seem to have reached a deeply ingrained understanding of what it does and doesn't do for them, and the control ultimately flows from that.
Read closer, "naturals" means they have talent at the skill, unlike the contrasted people who have a harder time about it in parent comments. If you are a natural, it doesn't mean you go pursue that skill either. You also get hyperfocus with ADHD.
I'm sort of inclined to agree with your premise that ADHD may describe how a patient presents without describing the underlying faulty physiology; but, at the same time—it's all about attention.
It doesn't matter how you get there—mechanisms that can improve executive control and control over the mind's salience network will greatly end up benefiting those who suffer with ADHD. Those who practice mindfulness meditation—ADHD sufferers or not—show strengthened neural circuitry in both executive control and salience networks. Head trauma, environmental factors, genetics or what have you; working to strengthen these networks is a good thing.
For some people with ADHD, this will work very well, others will not. Some with ADHD are already naturals at mindfulness because they have really bad time blindness. They are always, a bit too in the moment and low anxiety.