I'm autistic with delayed sleep-wake cycle. For autistics DSWPD is pretty common. There's just no fixing that for the vast majority of us, we're just expected to follow strict schedules and if we are underslept, too bad for us.

ND people get this pretty badly. 2023 study: The incidence of sleep problems in ASD patients ranges from 32 to 71.5%, especially insomnia, while an estimated 25–50% of people with ADHD

Insomnia is different, but tbf, insomnia for many people can't be treated well or if not at all. CBT is helpful if you look at the studies and ignore the follow up studies showing relapses between 40-70%. We can stuff people with melatonin and hypnotics but after a while that no longer works. So looking at this, it looks like things like drugs and CBT can help 70% of insomnia sufferers but the relapse rate is as high as 70%, so we're looking at people who can actually be cured as low as 15-20% of total insomnia sufferers.

Its not caffeine or screens for us, its just how the machinery of the human body works. This is like telling a depressed person to just 'cheer up.' I'm glad that worked for you, but your story is just an anecdote, and the science for this is still pretty dismal unfortunately.

The science can't work because at this point we're going against our nature. A lot of people cannot subscribe to a modern industrialized sleep schedule because its not natural for us to have extremely strict sleep and wake times.