Since neither you nor I have been to space, it's safe to say none of us have seen it. And in flat earth theory, the Sun is in the earth's atmosphere.
Say what? The Sun exists in the atmosphere?? How big is the atmosphere in your opinion? The sun is supposedly 3000 miles away. There are plenty of videos of people launching balloons past the vast majority of the atmosphere - about 20 miles up. The Sun is clearly not in the atmosphere.
I've already cited a NASA article that explains that fire in zero gravity behaves differently: Fuel comes to the fire.
Please tell us why you think the sun exists in zero gravity. How did it form?
How hot do you think the Sun is that it requires such high amounts of mass/energy?
We know how hot it is by the radiation it emits. Please tell us how your flaming ball generates x-rays.
I believe because proponents of a round earth out-rivaled their competitors and gained the upper hand in academia.
Please point us to a few prominent FE academic and the work they've done.
The Sun in flat earth theory would be located in the earth's atmosphere, not in space. And it makes sense. This flat earth model of the Sun explains why earth has so much water and why other planets don't.
Ganymede has more water than Earth and it is only a moon. Enceladus is also covered in water. (Frozen surface, obviously)
Water vapor forms into clouds, which then create their own energy (lightning). The lightning would perform electrolysis to convert h2o into hydrogen and oxygen molecules. These separate gases would then move toward the least dense area (the Sun), according to diffusion. But it's irrelevant if I cannot fully explain this. Explaining the phenomenon is not the same thing as explaining the mechanism for the phenomenon. Just because I may not be able to explain certain mechanisms for the theory, it doesn't affect the theory itself.
The problem with your theory is that it is unfounded, not backed by observation, and, frankly, impossible. Other than that, I think you're on to something.