Figured it out :D!! This method uses an actual Texture Cube asset so the mip maps and filtering are done correctly, and also the texture is actually streamable as well.
I have a material function that takes in a constant (0-5) to return the UVW of a face of a cubemap:
I also apply that EAC distortion function I posted originally when feeding the Texture Coordinates in, so that everything looks proper:
I used the fast arctangent node instead of the actual one since the difference is negligible, but for accuracy you can just swap it.
The face number is gotten by using Vertex Normals:
This is the cube mesh I’m using if someone else needs it, make sure you enable High Precision UV’s on LoD 0:
ultimate cube skybox.fbx (11.8 KB)