The issue is not the shape of the sun. Suppose you are in a dark room and someone across the room is holding a flashlight poining down. Due to dust in the air reflecting light, you will see the beam, like you see searchlights at grand openings and shooting down planes in WW2. The air also diffuses the light, as you see for a short while after sunset when it is still light after the sun is below the horizon. An hour after sunset, you would see the cone of light shining down, as I said, like a giant spotlight pointing down in the distance.
And you WOULD see it. You can see stars all over the dome everywhere on earth, so we know we can see across the entire diameter of the earth.
FE has never explained where the sun goes at night and why you can't see it off in the distance, yet you can see stars over the entire dome. The sun that was so bright at your noon is not just distant at nioght, you can see stars through it. If it isn't simultaneously bright to those under it and invisible to those seeing stars right through it, where is it?