I am going through the tutorial by WorldofLevelDesign. There is a step when we create a new level and use that “TimeOfDay” template or preset. Here are two screens, first one is mine. Difference is obvious. On my side, this looks dark as hell, yet the sun is there up in the sky.
Look up Lumen lighting in the UEFN documentation, it goes over all the settings. I remember them covering this. Something in your settings is incorrect. You should be able to find the answer there.
Good luck!