5-HT1A may be a tradeoff between poor executive function (too low) and poor memory formation/learning (too high).
CBD, like Buspirone, is a fairly selective 5-HT1A agonist (partial agonist, in case of CBD).
Buspirone has proven therapeutic benefit in double blind trials of ADHD, but not to the extent of Ritalin. Buspirone combines 5-HT1A agonism with α2A antagonism, which is likely part of its therapeutic benefit for inattentive type ADHD (but may provide negative outcomes on hyperactivity, if monkey models are related).
But in any case, there’s good basis to believe CBD could benefit ADHD, particularly those “high functioning”. I would not expect it to help all.