The "earliest wake time" setting used to work for this. My sunrise is 5:15.
I set my earliest wake time to 3:30am.
I remember if I would stay awake all night at 3:30am I would be flashed with bright light.
My reason is I want to wake up at 3:30 am I managed to wake up today at 4:am.
My screen was still red 2800K
Only at 5:59 it was disable even though my sunrise time is 5:15 as per my location
I don't see any setting and I am pretty sure when I used to wake up early I would see my bright screen and that helped me stay awake if I didn't want to sleep. I would just work on my computer in bright daylight setting and at 4am all my sleep would vanish.
Now this is making me drowsy
I would also like a nice low dip from 5:pm till 7:pm a nice curve.
but can't set that. My sunset timings are 6:45pm.