Even so, this can be changed via environment. I had a big predisposition to being a night owl in the past, often sleeping between 1 - 3 am, but after I enlisted

Even so, this can be changed via environment. I had a big predisposition to being a night owl in the past, often sleeping between 1 - 3 am, but after I enlisted in the military, being an early bird has stuck with me ever since. I often wake up 5-6 am and go to sleep ~10-11 pm, sometimes closer to 9, sometimes later. For me, not using alarms to wake up in general, and sleeping earlier works wonders. I also adjusted to having less sleep as a result of the forced sleeplessness of military life.