I have a different perspective on this, because my child is older - 12 and in middle school. What I thought was intolerance to boredom and lack of patience for certain tasks in the elementary school was in fact some struggle with focus and sustained attention. I remember thinking that her mind restlessness/daydreaming was a good thing and more or less an indication of creativity potential and ability to think out of the box, but I no longer think like that.

Elementary school being easy/boring was actually a very bad thing because it didn't teach her responsibility, study skills and work ethics level, which are critical in the later years of schooling. She flew through minute math or book reports or "science", never needing to practice before the test day or anything else.
On the parent's side, the school being easy didn't flag the need for more organizational/structural support at home.

PSI+WMI equates to what psychologists call executive function or EF. What they say is that typically, unless the child is very obviously affected, the EF doesn't play a big role in child's life until much later, but once it does it may have a bigger impact on child's life than the first cognitive scores combined (GAI) and I tend to agree with that. My daughter currently scores at the level of PSI+WMI on standardized tests instead of VCI+VSI+FRI as she should. PSI+WMI being low seems to be common in high FSIQ individuals, and it is hypothesized that it may account for a significant rate of high school dropouts among high IQ individuals (up to 20%, which is higher than for kids with above average IQ).

That's why I am here. I am absolutely sure it isn't too late and I am looking for solutions. I don't like the idea of medicating my child, and the current research shows little effect from stimulants on the academic performance, but it does seem to address the executive function in the child to some degree and I am 100% sure that lower PSI+WMI scores and somewhat lower academic achievement are completely related to that at the older age.

I want to start small and see if simple changes in routine, diet may help, but don't know where to go with and there is so much "noise" on Google as to what actually helps, specifically in case of gifted children. I've read that 100mg of caffeine has the same action as low-dose stimulants and is safe in older children (she is physically a young adult). 100mg is an equivalent of a cup of coffee. The research is iffy on this subject for ADHD patients but seems to support the idea of memory, focus and attention increase in otherwise healthy people. What do you think? Is that crazy or us, adults, clearly benefit from it, so why can't an-almost-adult do it too? Would CBT therapy be useful (cognitive behavior therapy)? Any recommendations on how to boost organizational aspect of her life?