@Owl @PeachySummer @AlabasterBrick @SK1ZM @matty @DEERBLOOD Have you considered the effects of blue light radiation? It is damaging to melatonin and prevents it from building up, the building up of melatonin causes your eyes to get tired and is one major factor in sleep health. Almost all digital screens cause blue light. The phone and compute kill the sleep.
All throughout the day your body also builds up adenosine, its similar to melatonin but for the body, many chemicals effect this, caffeine being the most well known as it inhibits the the receptors that adenosine binds to.
The opposite of that is the cortisol response, if you are stressed it can build up when the body is not functioning as it should, cortisol can spike at the wrong time, causing sleep difficulty.