This reminds me of "The Calculus Trap" -
https://artofproblemsolving.com/news/articles/avoid-the-calculus-trap"If ever you are by far the best, or the most interested, student in a classroom, then you should find another classroom". This can be a challenge in most school systems.
My D has thrived being involved in a local math team that has attracted about 30 of the top math students from this half of the state, led by college grad students.
She's at about a 99.6 average from 7th-early 10th grade at school, but typically scores about 10th on her team in competitions. She's learning a lot more, and is a lot more interested, at the program than she is in school. They study advanced topics, and they move fast. (Want to know why e^(pi*i) = -1? She can explain it to you. Euler's totient function? No problem...)
We've found similar stretch/enrichment programs through various programs in the area. CTY, for example, has fast-paced HS science courses. A full year of honors physics, for example, in a 3 week camp.
It takes some work to find them, but I believe programs like these are better solutions than just moving up to the next grade in school.
From my own experience - accelerated one grade and my parents declined the suggestion to move another - Saturday classes at our local college were favorites of mine.
