How to lessen the difference between daytime and nighttime in a building's interior

In a game I’m making, I have a time controller that rotates a directional light to emulate the sun. It works fine, but for some reason when it’s nighttime (X rotation is 200), the ceiling of a building darkens to near black even though there are four point lights set up.

Here’s what it looks like during daytime: 119167-screenshot-45.png

And during nighttime: 119168-screenshot-46.png

What I’m looking for is how to make the difference between daytime and nighttime not so stark; i.e., maintain a bit of light on the ceiling at all time.

Good day.

Why are you using a sun if the scene is interior?

But, anyway, i recommend you to create another directional light at oposite direction of the sun, with much less intensity, and with blue color, to emulate the moon, and rpeventing to have zones at “shadow side”