I relate to this so much:
It is hard to describe and may sound like I don’t have ADHD, but I have simply learned over the years of my life up to this point how to manage my symptoms, but they come out when there aren’t expectations placed upon me.
I’ve got inattentive ADHD, though sometimes I do get very fidgety, too. My son is 8, diagnosed with combined ADHD like you, and he feels bored all the time, too. His teacher offers flexible seating, but that still isn’t moving around.
I wish I could share solutions, but we haven’t figured it out either. We’ve tried fidgets and chair bands (that you can bounce your feet on) but they don’t help much. Just know you’re definitely not alone in this!