Some Flatearthers like to say that astronomical predictions are merely based on patterns, and that such patterns would exist whether or not the earth were flat. Hence RE = 0, FE = 0. It’s a draw.
But science itself does not measure success in that way. First, science requires an explanatory model. And it rates models in the following way. (1) Prefer a more accurate model to a less accurate one. (2) Given models of roughly equal accuracy, prefer the simpler model to the more complex one. (3) Prefer any model to no model at all.
So, take the pattern we observe of the sun rising, then setting, then a period of near darkness, then sun rising again. This is a well-observed pattern. Then the current scientific model is that this is caused by a relatively stationary sun, with the earth revolving on an axis or rotation. This is more than just noting the pattern, it is explaining it. An earlier model (the Ptolemaic) has a fixed earth with the planets, stars and sun revolving around it. Both models score roughly equally except for planetary motion. The Ptolemaic model does explain these, but it is more complex than the Newtonian system that replaced it, so prefer the current heliocentric one, which is simpler.
Then we have the Flat Earth model, which aims to explain the day-night pattern by a sun rotating around the flat disc of the Earth. How does this score? Well it’s a model of sorts. However, it does not accurately predict the angle that the sun appears each day, the position it rises in the east and so on. So it’s not really a model, and certainly not an accurate one. I have seen models that explain the observations in terms of light bending and so on, but (a) these are based on the RE system anyway and (b) they are far more complex.
In summary, it’s not about which system is ‘true’. Rather, which model best explains the observations. The current scientific model beats the flat earth one based on the scoring system proposed by Science.
Of course there may be other scoring systems. Perhaps someone would like to suggest one that favours flat earth models?