Both of my kid have been homeschooled up until 5th grade. At home they used to do less than 20min per day of ’school’.
After a few month at school they now find the pace incredibly slow and they can’t stand the waiting they have to endure.
They both score 80-95% in all classes.
My son is learning programming and video editing and piano by himself, my daughter is writing small novels in a second language.
We didn’t teach them much at all, they mostly learn just by themselves.
They now want to go back to homeschooling so they don’t have to wait to learn nothing.
They might be a bit gifted, but I think that the main difference is that they didn’t go to school, they didn’t get used to waiting and learning at the same pace as everyone. I think that most kids a much more capable than we think.
Now I think that unschooling + a bit of tutoring would be incredibly powerful.