I'm not sure it's 'owlishness' or if it's delayed onset sleep disorder, but my body seems to just want more hours in the day. More to be awake for (20 ish) and more to be asleep (10 would be good). If I was left to control my own schedule and didn't have to consider everyone else on the planet I'd probably get up six hours later every day...
I've tried making myself go to bed, and sometimes to sleep with chemical help, It doesn't seem to work for more than a few days. I don't seem to have a reset button I can find.
Getting up at 5am regularly isn't really a choice I can see making, however motivated, because 5am would come and my only thought would be how quickly I could go back to sleep, shortly followed by seething, loathing hatred for whatever had woken me. Similarly going to bed at 10 results in me laying there for several hours awake.
I envy people who regularly get tired in the evening rather than waking up and wanting to do stuff when the rest of the world shuts down.