I think if I was a child again in today's world, I would probably prefer some long-term support outside of the school system (so I don't lose the support system when I change school). It should be some organization with more people (so I don't lose the support system when one person quits). Something available both online and personally, where I could ask questions, where people would give me study resources, guide me through my projects, and also look at my finished projects and review them seriously (not "wow this is great for your age", but "you did this part correctly and that part incorrectly, see me again when you fix it, and here is something related to study"). And while supporting me on my desired way, they should also sometimes challenge me to try something new. I wouldn't need anyone to tell me that I am special (that just creates anxiety: what if I stop being so special?), but I would like to have as much help as possible to become stronger. Unfortunately, I feel our treatment of gifted children is mostly "you are so cool, and we actually have no idea about what to do next, so just enjoy your coolness as long as you have it".

Perhaps something like REU programs for high school students that run throughout the year (which would be possible because of the low workload in high school). There are some REU-like summer research opportunities for high school students, and I mention some in my other comment. But it may be infeasible to expand these programs simply because there aren't enough faculty members who are both willing and capable of mentoring high school students. And, of course, there isn't always a university nearby.