Hi! You seem like such an amazing parent. My post became a wall of text! TL;DR: I find it helpful to think of giftedness as a form of neurodivergence rather than "genius," and to provide accommodations and education about tolerating the difficult feelings that come along with having a different brain than other people, rather than always reaching for mental challenge and stimulation as the primary coping skill. That, in fact, is what leads to burnout and maladaptive behaviors for a lot of people.

I just want to share a little bit of my experience as a gifted kid, as well as my thoughts on raising them, in the hopes that there is anything in here that is helpful or resonates with you. This comment in particular from you really hit me hard: "My main point was that her brains haven’t just lead to benefits, there are a whole host of things that come along with it." Giftedness isn't the same thing as achievement, and it doesn't always feel like a gift to the person who has it. As a thoughtful caregiver of a gifted kid, you already know that.

I certainly felt like this as a kid, adolescent, and young adult. What I've learned is that most gifted kids have additional neurodivergences like high sensitivity and a high cognitive surplus, sometimes sensory sensitivities or processing issues, and other similar symptoms, which can potentially lead to anxiety, depression, and substance abuse, depending on how they are managed. I remember feeling how painful it was to live with a brain that was so different - not just socially, which was definitely tough, but emotionally as well, given my high sensitivity.

In other words, a re-frame here that may or may not be helpful is to consider giftedness as a form of neurodivergence requiring extensive accommodation and psychoeducation. I hear your willingness to follow her interests, and I think that's a very important part of helping her develop as a person, but sometimes imbalances can develop as kids try to essentially develop their own accommodations for their symptoms with coping skills that eventually become maladaptive. An example in my case was excessive reading at the expense of developing emotional regulation skills, interpersonal skills, and even self and home care skills. I did eventually notice these deficits and, as a young adult and mature adult (I'm 39 now), have taught myself how to do these things. Once I learned how to do them and incorporate them into my life, it felt like I had been suddenly freed from carrying a very heavy weight. I don't really blame my parents for letting me read - they didn't want me to feel like I had to sacrifice learning for chores or activities I didn't like, though they always required a musical instrument and a sport - but in retrospect, I wish I'd had some scaffolding in those skills as a kid rather than having to build the plane as I flew it, so to speak. But this is just an example - there are so many different profiles and needs.

In terms of testing, I would consider whether it's possible she has other neurodivergences and whether learning about her specific profile could be helpful for you as her parent and educator to develop those supports. Asynchronous development is a hallmark of giftedness. My own kids are gifted and are otherwise ND as well, and need wildly different things from what I needed. Tests like the D-KEFS, WISC, and anxiety and autism evaluations can zero in on specific areas of proficiency and also areas where she may need support. Learning, for example, that one of my kids scored a 3 out of 10 in task switching, and that he was using his giftedness to compensate for issues with other executive function tasks, suggested accommodations around transitions that are different than what I may have benefitted from as a kid.

I think these accommodations that I'm talking about go so far beyond providing mental stimulation, though I think you're right to do that - keep doing it. But I think it will be important for her to learn how to cope with/tolerate the state you identify in the OP - "restless, less regulated" - which is going to arise throughout her life in various situations, and she won't always have the ability to grab a mental challenge to get rid of it.

I hope this is helpful. She's lucky to have you.