Do you have any input on whether you think this goal is an appropriate concern in the longer term, and if so how you might want to see a school address it? The Montessori school we’re considering says that it is possibly spending a greater amount of time imparting organization and time management skills by asking children to manage their own time all day long. They give very limited homework, unless a child doesn’t complete work during the school hours and must thus complete it at home."
The goal is most certainly a worthwhile one. My observation is the same: many GT students struggle with executive functions and study skills later in their lives because they had no incentive to develop them during elementary and secondary school. (I don't think I really learned how to study until graduate school, and I'm not sure my extreme PG sib ever has--though it hasn't impaired any major life outcomes.) As to the means, I would agree with the Montessori school. Further, in my experience, the response of GT students to volumes of work principally for the sake of learning time management (aka, busy work) can be even more damaging than the absence of study skills itself. I have had enough students in this situation whose response was to deliberately sabotage their own academic performance--as a means of either protest for meaningless busy work, or of having a voice/choice in their own, overly-adult-managed educational experience--to suspect it is a real correlation, with possible causality.
Creative, abstract, divergent thinkers generally do not take kindly to demands to churn out masses of meaningless check-the-box work products.
I would prefer to see study skills and EF develop because a learner is being instructed and challenged in the quality of their work, in the zone of proximal development. so that the exertion of work ethics, study skills, and organization are in service to personally meaningful learning. This is what NT learners more often receive, because conventional schools do instruct them in their ZPD. Why should academically-advanced learners have to learn it using drudgery? If it isn't possible to find this in academics, one can also create meaningful learning opportunities in other contexts, such as sport, art, music, technical trades, hobbies, et al.
I have talked to a parent whose children attend this Montessori school, and she says they have been willing to seamlessly allow her children to visit older classrooms for instruction in subjects where they are working above grade level. That sounds promising, but her kids are outliers in working that far ahead.
Right now our daughter is reading because she wants to.
Your DD is also an outlier; perhaps you might consider that reading for pleasure at 2.5 yo is not quite typical?
That the school has been willing to accommodate outliers appears promising.
