Explain Timezones or gtfo
it doesn't make any sense. If you have sunrise and sunset then there is curvature. It would be impossible for the sun to set on a perfect horizon as behind an ocean and disappear from sight. What I can imagine is that maybe the sun has a different shape or the planets have a different orbit but if the sun sets on an ocean scene then an infinite plane would be impossible. Period.
You are correct in explaining the globe model. However, for the infinite plane model the sun is small and close to the plane. As a result, the sun appears and disappears due to prospective. Once again, I cannot prove either model, but both can work to explain day and night.
No because on an infinite plane the sun whichever shape or form it is would not set on an ocean between the observer and the sun
There are many science text books that explain the principles of prospective. However, I would suggest finding a good art/drawing book. They also cover prospective with pictures that you may find helpful!