It would have been a lot more comfortable getting in for maybe 10am and leaving at 5pm. I remember sometimes you'd have a special day in the week where there were no classes in the morning, meaning you started late. And then maybe an extra lesson or activity in the evening. But similar length of day, shifted, felt much better.
Having worked for longer than I went to school for now, I think the school calendar needs an overhaul. There's no reason to take a huge holiday in the summer. In fact, why have any holiday at all? Just have school on all the time, and let people take holidays whenever they want, like at work. You won't forget things as easily taking week or two week holidays as against 8 week ones. Also it means parents won't have their holidays dictated by the school.
Within the day, I also wonder about the frequency of context switches. You might be taking 6 classes a day: PE, French, Math, English, History, Physics.
Now image you are coding, and you do this: Troubleshoot the rendering issue on the website, install a lock free ring on your trading system, write a SIMD function in CUDA, fix your cmake file dependencies, add unit tests to your CI script, and set up Kubernetes.
Would you do those things one at a time, or in little pieces where you have to pick up where you left off arbitrarily?
It seems you should have large blocks, maybe just morning and afternoon, rather than dozens of little classes each week.
But then possibly as a teenager concentration is an issue, I don't know. I certainly think it's better to focus on one thing at a time, quite a long time, before changing contexts.