Teenager With Chronic Insomnia

I've had difficulty falling asleep since I was a teenager (27 now), but over the years the problem has only gotten worse.

To put it as simply as possible: No matter how tired I am during the day, I am never tired or sleepy by the time I have to go to bed.I believe this is partly a case of DSPD (delayed sleep-phase disorder), because I do tend to fall asleep faster if I stay up until well past midnight. The problem is I have to get up at 8AM and there is no way to get around this (I own an independant store that opens at 9AM).

I am not stressed out when I go to bed or thinking/worrying too much, I am simply not tired. If I go to bed at 10PM it feels like I am trying to sleep in the middle of the afternoon. I ted to fall asleep between 12-12.30 at night which is around 1 to 1,5 hours later than I would like to fall asleep.

Going to bed earlier has almost no influence on when I fall afsleep: For example if I go to bed at 10PM I'd fall asleep at 11.45, while if I go to bed at 11.15 I'd fall asleep at midnight. 30 minutes of laying awake is the minimum though and I consider that a REALLY good night.

To make matters worse, I am a competitive athlete which makes a good restful night's sleep all the more necessary. This is also why I have stubbornly only used a few types of sleep medication, because it is EXTREMELY important that my reflexes/focus is not impaired the next morning, which is a side effect of nearly all sleeping aids. What I've tried:

1mg lormetazepam: Slept fine but did not feel rested and felt groggy the next day

3mg melatonin: Had no influence on falling asleep and woke up in the middle of the night way too energized like it was the middle of the afternoon.

Passiflora extract: no effect

ZMA: no effect.

The bottom line is: I sleep 6-7 hours a night, I only feel rested after 9-10 hours, and no matter what I try, I can't seem to fall asleep quicker, or even be tired when it's time to go to bed.