If I force myself to go to bed at 10PM I just end up frustrated for hours on end and actually sleep less than if I go around 12-1am. That's the absolute earlies

If I force myself to go to bed at 10PM I just end up frustrated for hours on end and actually sleep less than if I go around 12-1am. That's the absolute earliest I can - in uni I regularly didn't sleep before 4am. You can't just force out a habit that built up over (in my case) a very long part of your life.