Directional light inside skysphere (mesh)

Short version:
I made a custom skysphere to create a space scene. It is an actual mesh. I removed the original skysphere.
All objects are within my unlit skysphere mesh. (I tried a cubemap onto the original skysphere before, but it was messed up on next load). When I built the lighting with a directional light, all of my meshes turn black (except for the skysphere). Replacing the directional light with a big spotlight didn’t work. Building Lighting would remain stuck at 0 for over an hour. For additional information and reasons behind the choices, please read the long version. View Screenshots for info about the settings. Looking for a fix for either: 1: Getting my lighting to work (directional light or otherwise). Get the default Skysphere to display my skysphere properly.

Long version:
So I am having quite the struggle with custom skyspheres.

I am currently trying to make a arena that finds itself in space (Inspired by the movie Ender’s Game). However the skysphere is giving me problems. At first I did it the way the engine wants me to. Make a cubemap, get it working inside the blueprint for the default skysphere (or make a similar new one) and all is fine and dandy. and it was… for 1 day. When I reloaded the project a few days later (no updates took place to my knowledge) It was all messed up. My sphysphere was black, the material still in place. However inside the material it gave an error about my cubemap. I tried re-import and remaking the material, but it didn’t help.

So I found a new, and more simple way: Make a cube in 3ds max → add 6 images (1 on each side of the cube) → Turbosmooth it into a sphere and you have a spherical mesh that is your skysphere. Seemed to work fine, except now my sunlight isn’t working anymore ;(

When I use directional light, everything turns black (my static meshes that is). My first google searches suggested that the sphere shouldn’t cast shadows, but it is an unlit object so it isn’t as I cannot even change it (The box is greyed out).

I tried removing the directional light and go with a big f-ing spotlight to light my scene as a stand-in sun. However this way my lighting would never build (Stuck at 0 for over 30 min).

Is there any way to make directional light work inside of a spherical mesh? Because it seems to be the only thing with enough light that actually builds inside of the scene. Any decent alternative to lighting is also very welcome.
In case someone knows an up-to-date way to make the default skysphere work to appear as space, I would also like that (because then I can use the sun as usual).

Here is some info and screens of my current scene:
Active items: PostProcessVolume, LightmassImportanceVolume, Skylight, SphereReflectionCapture, Character and meshes from first person kit, my own static meshes, my custom skysphere.

My scene before building the light

My scene after building light with directional light.

The skysphere

One of the materials

One of the textures

Have you tried setting the skysphere to movable ?
It is also quite uncommon to use static lighting in space scenes.