Hello pkringen,
I have a couple of suggestions on how to create a Night Sky feel. Firstly you need to select your SkySphere and not let that reference any light source so you can change the Sun Height. Use this in conjunction with your Global Post Process volume to increase the night time feel by adding scene color and other cool effects! This should get you on your way to getting a nice night sky.
Sky Sphere Blueprint Settings
Global Post Process Volume Settings
