Like most of you, I myself have been investigating how to sleep better for quite a number of years.
The problem with most of what I read here is that you're (which is what I did too) using anecdotal reports to experiment on yourself to come up with something that you feel works for you.
I eventually stumbled on a podcast by Andrew Huberman (Neuroscientist/ophthalmology at Stanford) where he shares details of their research.
Just a couple of items from my notes (and there are much more)
- The quality of light during sunrise, as perceived through your eyes, sets off a "count down timer" of sorts in your brain
- The quality of light during sunset, reduces the sensitivity to light you encounter after sunset
- Your eye's structure is such that light coming from above enters the eye different from light coming from below.
- - Which is why in the morning you want to go outside to allow the sun light from above to enter, and,
- - in the evening to switch off the ceiling lights and instead use lamps that are set low.
- The old story about "don't use screens and bright lights in the evening" is true to some extent, but there is more to this
- - Candle light ; I've decided to go to the extreme, and switch to candle light at 9pm, set at desk or floor height
- - - I use this time to perform activities that dont require a lot of light (tidying, dishes, clothes, etc)
- circadian rhythms are key
- - when you eat and exercise is a way to set your clock
...
It just goes on and on with details that I would've taken a lifetime to find.
I'd suggest you start at ep1 as it sets you up with some understanding of how your brain works,
ep2 & 3 is all about sleep
ep 4 - goes into finding your temp minimum, jetlag, sleeplessness
I'm sure beyond ep4 [4] the topic of sleep will come up again, as it is the #1 thing that determines the quality of everything else in your life.
[1] Podcast https://hubermanlab.com/category/podcast-episodes/
[2] Notes https://podcastnotes.org/category/huberman-lab/
[3] Transcripts https://github.com/lord-denning/Huberman-Lab-Podcast-Transcripts
[4] Search 'sleep' https://www.google.com/search?channel=fs&client=ubuntu&q=sleep+site%3Ahubermanlab.com%2F