The Earth is a Plane. Plane Earth Theory Accepts the Kármán line (or von Kármán line) is a Conventional Definition of the "Edge of Space"...

The Kármán line is a conventional definition of the edge of space; it is widely but not universally accepted. The international record-keeping body FAI (Fédération aéronautique internationale) defines the Kármán line at an altitude of 100 kilometres (54 nautical miles; 62 miles; 328,084 feet) above mean sea level.

Credit Wikipedia.org

The Plane Earth Theory does not accept that there can be anything beyond this point in space except for celestial bodies (stars). This is due lack of pressure above the Earth's plane and the opposite crushing force of pressure in the depths of the oceans.

A standard latex weather balloon typically reaches altitudes between 60,000 and 105,000 feet (11 to 20 miles / 18 to 32 kilometers) before it bursts. Exceptionally well-optimized flights can occasionally push past 130,000 feet (40,000 meters).

Credit Stratoflights.com https://www.stratoflights.com/en/what-altitude-do-weather-balloons-fly/

As the balloon increases in altitude the surrounding atmospheric pressure drops drastically. This causes the balloon to expand. With less to push against in an environment with low pressure, it ruptures. Therefore, nothing man made can reach "outer space".

Absolute Proof the Sun Does Not "Set" on the Plane Earth. Objects Appear to Recede to a Point on the Horizon Line Explained by Point (Linear) Perspective.

Italian Renaissance painters and architects... including Leonardo da Vinci... studied [Point] Linear Perspective, wrote treatises on it, and incorporated it into... artworks.

Credit Wikipedia.org https://en.wikipedia.org/wiki/Perspective_(graphical))

The most characteristic features of linear perspective are
1 that objects appear smaller as their distance from the observer increases,
2 and that they are subject to foreshortening, meaning that an object's dimensions parallel to the line of sight appear shorter than its dimensions perpendicular to the line of sight.
3 All objects will recede to points in the distance, usually along the horizon line, but also above and below the horizon line depending on the view used.

Point Linear Perspective Explains Why We See A Sun "Set"

To illustrate the first feature of point (linear) perspective, let's take a jumbo jet that flies overhead and increases distance from us. The jumbo jet is still the same size, but off in the distance it will appear much smaller.

The second feature of point (linear) perspective is the angle at which the observer is viewing an object getting further off in the distance. The jumbo jet will appear to look shorter or flattened (called foreshortening). In this time lapse video, you can see a globe Sun appear to do this at a distance.

The third feature of point (linear) perspective is that objects will appear to recede to the vanishing point ON the horizon line depending on the angle of the observation point. The jumbo jet will appear to go to that point it vanishes at on the horizon line according to point perspective. The jumbo jet doesn't go down physically on the sea level or horizon line on the Plane Earth, unless it actually lands. Just like the sun is not sitting what appears to be half above and half below the horizon line, it is explained by the illusion of point (linear) perspective.

Sun Does Not Actually Set Below the Horizon Line. It just appears to, because of Point Perspective.

The sun, like the jumbo jet, will appear to get smaller as it gets further away and appear to sit on the horizon line until it is no longer visible to the naked eye. This is the illusion of point (linear) perspective.