I have no advice, but just wanted to tell a short story. When I was around your son’s age, I was constantly told I was “gifted” and was simply “bored” in school. I, honestly, don’t remember being all that bored in school (except maybe during history lol). This was in the mid-80s, so girls were never diagnosed as ADHD. Fast forward to high school, where a teacher literally yelled at me, in front of everyone in the class, “Take some Ritalin!!!” because I was always so hyper and in trouble. I didn’t get diagnosed until I was 20 and starting college because by then the academic demands were too much for my made-up coping skills. I wanted to yell at every person who ever said it was just because I was “bored” with the “easy” schoolwork. So, then once I was “challenged” in college, everything fell apart; whereas, if it really was because I was bored, then college should have been amazing.
I would get a second opinion and hopefully get your son the help he deserves. Best of luck to you both!