I do everything by the book, still no sleep

I’ve had insomnia since childhood. Back then, it felt pretty cool to read at night or listen to music on headphones, pretending to be asleep when my parents checked. As I got older, the lack of sleep started to mess with my life, especially with my job. Now I follow every rule, skip naps, don’t drink coffee, reduce sugar, take melatonin, go to bed before midnight, and I still spend most of the night staring at the ceiling or drifting in and out of shallow sleep. I don’t ruminate, most of the time, there are no thoughts at all, just emptiness. What’s wrong with me?