Another thing to consider regarding sleep (you can call it life hack) is that a whole sleep cycle takes about 90 minutes. Thats why it is better to sleep 7.5h instead of 8h because you are in the middle of the cycle for the latter.
That way you will always wake up in a light sleep state theoretically. I tried that the last years and most of the time it works great.
And in combination with a fixed schedule, I don’t even need an alarm clock anymore.