My wife went to this indian alternative education school, a boarding school called Rishi Valley. They've opened many branches now, though I can't speak for the ones I don't know, all based on the philosophy of Jiddu Krishnamurti; you can read more about them here:
https://jkrishnamurti.org/schoolsRishi Valley's teachning style is, honestly, what I wish my education had been. I remember being a kid and asking my teacher for "more", questions about what happens _beyond_ what we had just learned, and them saying "don't worry about it, you'll learn next year".
Rishi Valley's approach is "why don't you come later and I'll show you? is anyone else interested?". They really try to emphasize learning for the sake of learning, and kids can choose from multiple subjects.
The teachers are often PhDs who have decided that they care a lot about education. Since it's a not for profit school, they're not paid a lot, but they live on campus, and get to interact with kids all day everyday. Most of the money the school gets is put back into rural education.
Now, the transition back to the "standard" system when the kids have to go to college is not smooth. Most of the ones I've talked to mention that they were extremely overwhelmed with the "rat-race" and the fact that everyone was so competitive, where they had been focusing on learning for the sake of learning. Everyone I've met from this school is very good at critical-thinking, and they don't accept a conclusion just because "someone said so", they will fact-check, do their own research, debate, ... Which I think should be the goal of education.
My anecdotal experience is that they overperform their non-weird-school peers though. But is that due to the teaching itself? Or is it maybe because the kind of parents who would put their kids in this school already did some sort of ground-work? I'm not sure!