I’m so sorry to hear that your son is enduring such hardship finding the right medication and dosage for his ADHD. The options can feel overwhelming at times, so we like to refer often to this chart: https://www.additudemag.com/adhd-medications-list-chart-stimulants-nonstimulants/
You’ll see that it includes both stimulants and non-stimulants, and each medication clicks through to a page with more information.
I would also recommend listening to last week’s webinar about this very topic with Dr. Thomas Brown at https://www.additudemag.com/webinar/optimize-stimulant-adhd-medications/
Best of luck!