Windows 10 night mode can either be turned on or off. But I would prefer to start activating it step by step, like dimming a light slowly. For example, starting at 8pm with 10% and then adding 10% every 15min or so. How could this be achieved?
I use f.lux for this:
f.lux makes your computer screen look like the room you're in, all the time. When the sun sets, it makes your computer look like your indoor lights. In the morning, it makes things look like sunlight again.
Tell f.lux what kind of lighting you have, and where you live. Then forget about it. f.lux will do the rest, automatically.
It does a gradual change of the screen brightness/contrast/colour.