21/09/21 (2) Sleep problems

I've always been on the nocturnal side and for many years it's been my habit to stay up after midnight (when I often feel at my sharpest for the whole day), catch up on recorded TV, do computer stuff, and etc., and get to bed somewhere between 02:00 and 02:30. Recently I've started falling asleep in my study chair at 01:00 to 01:30 and waking up again the wrong side of 03:00. As I'm also tending to wake up earlier than before, the result is not enough hours of decent sleep, even though I don't need many. I've been setting two alarms in my study for just before 02:00 (Alexa and phone) but I just sleep through them... Not at all sure what the answer to this is. Long experience tells me that if I try going to bed earlier I just don't sleep, so that wouldn't help.