I hear you. I also know people with ADHD, and know how it affects them. We all know it is a struggle and I am not asserting you or any other person with ADHD is less of an adult for it. You bear that burden and everything that goes with it, and I respect that.

However, there has to be something that the human society should cling to. And that is the natural sunrise/sunset cycles of our environment. We cannot please everyone, but could you agree with me on this ?

How else could we structure our universities and workdays if not according to our natural environment? I sadly cannot think of a way that does not include layers and layers of renduncancies and around the clock university lectures which would cater to everyone, and ultimately to noone. As we would open a pandora's box of people waking up at 6am, 9am, 13am, 3pm, and imagine the complexity of catering to ALL of those cases.

It is interesting to see what Wiki says about the evidence for sleep hygiene. However, as of 2021, the empirical evidence for the effectiveness of sleep hygiene is "limited and inconclusive" for the general population[1] and for the treatment of insomnia,[2] despite being the oldest treatment for insomnia.[2] A systematic review by the AASM concluded that clinicians should not prescribe sleep hygiene for insomnia due to the evidence of absence of its efficacy and potential delaying of adequate treatment, recommending instead that effective therapies such as CBT-i should be preferred.[2]

https://en.wikipedia.org/wiki/Sleep_hygiene

I note that plenty of the things I'm told not to do, for sleep hygiene, are coping mechanisms for bad sleep. If I'm tired, then standing and sitting upright are unpleasant, so I'd rather do things lying down. If I can't get to sleep but am tired, then I'd like to do something to occupy my mind while I'm in bed. This creates an obvious confounding mechanism that would generate correlations (of the type "Bandages cause injuries!"). I also note with amusement "There is support showing positive sleep outcomes for people who follow more than one sleep hygiene recommendation"; if this isn't done by randomized assignment, then probably the people who follow multiple recommendations are (a) more motivated to fix their sleep, (b) less impaired in their ability to do difficult and inconvenient things, etc. One would hope that people would require much stronger evidence than correlations before making recommendations, but I have learned not to assume that.

Some specific things have been proven. For example, there have been studies where they had people sit in a relatively dark room, with an LED of varying color, and measured the amount of melatonin in their saliva, and found that blue and green light reduced melatonin significantly more than yellow and red light. But I would recommend reading the studies before putting stock in any particular costly recommendation.