The way our vision works makes everything converge to a single vanishing point on the flat horizon, including airplanes and the sun. Artists understand this. Airplanes appear to drop below the horizon when in reality they are flying level to the flat earth and never dip their noses down to account for any supposed curve. It's the same with the sun. It is moving across the sky on a flat circular path but it appears to rise and fall due to perspective.

78) From Anchorage, Alaska at an elevation of 102 feet, on clear days Mount Foraker can be seen with the naked eye 120 miles away. If Earth were a ball 25,000 miles in circumference, Mount Foraker’s 17,400 summit should be leaning back away from the observer covered by 7,719 feet of curved Earth. In reality, however, the entire mountain can be quite easily seen standing straight from base to summit.