I’m using translation so it might be a typo.
If I wasn’t working for mobile, I would add atmospheric fog and enlarge my sky sphere until the sun disk appeared but I can’t show my sun disk because atmospheric fog and sky atmosphere are not supported on mobile.
I can’t add the sun disk as texture to my sky sphere material because I need to turn on the light shaft bloom.
I had this situation because I misunderstood some things. The light shaft is not connected to the atmospheric sun. For the light shaft to work, the direction of the emission-intense area in the sky material must be the same as the direction the directional light is facing.
Also, if you are going to use a light shaft in a mobile game, I recommend that your light source material be smooth. If the surface is rough (like the moon), you will get an ugly appearance.
You can convert the Sky System to a material, that you then can apply to a sphere with inversed normals (color on the inside only, if the material is not set to “two-sided”).
Then you can use that sphere as your Sky sphere/skybox, but it will have the same visual effects as the sky atmosphere, including the sun disc.
To let the sun directional light shine through, just set the material so that it does not cast shadows (otherwise the light will be blocked by the sphere).