All those things sound very boring to me.
I can offer no concrete solutions.
However, I have a friend who graduated from high school #1 of a big class and 2 years early. His mom explained that if he made at least a 1400(of 1600) on his SAT, she would buy him a new gaming computer. He then proceeded to make exactly a 1400. No more. No less.
I recommend if you haven't tried already, an iteration to this approach using a sliding scale reward system. Perhaps a gaming pc with nvidia 4060ti up to *insert parental budget* in event of a perfect SAT score.
Ofc this only works if he's a gamer. I feel this type of system can be applied in many areas though. In my view, the clever component his mother applied is that the computer he earned was not just a desirable reward... It was VERY desirable.
My parents also tried this system with me. It didn't work as well. The reward was not sizable enough. It just didn't seem worth it. Too low value. Also, I already had a job and bought my own. My parents were unwilling to budget a sufficient reward. It's gotta be something he more or less is unlikely to be able to get via other means.
Now my friend is a physician. He graduated top of his class from med school. I think he's pretty content with life.
The bored ones can be a little more trouble sometimes. Fun breed though. Best of luck.