From some videos I've watched, looks like FE believe eclipses are caused by a black sun...
That's one theory ... rooted in the beliefs of various early civilizations that did believe in a "black sun". Much of the theory would depend on what the light source of the moon actually is, whether it's merely a reflection of the sun, and there's a significant body of evidence demonstrating that this cannot be the case.
One problem with eclipse theory is that the line put out by Neil de Grasse Tyson that the only thing that can produce a round shadow is a sphere. That's actually incorrect when the shadow is also ON a sphere. When a sphere casts a shadow onto another sphere, the resulting shadow is in fact a straight line. This has been demonstrated by FEs with models.
Another problem is with the selenelion.
I'll also have to dig up a video I saw of a solar eclipse viewed from a plane, and the demonstration that the shadows created would be impossible given the model where the sun is millions of miles away.
And yet another problem is that the umbra (or main shadow) of the moon on the earth is way too small.
NASA tried to explain it away by claiming that this is the "correct" model.
But this is utterly ridiculous. Given the alleged distance of the sun from the earth and the moon, it is NOT that much larger than the moon. In fact, the relative distances and sizes of the two is what they use to explain the fact that they appear to be roughly the same size in the sky, with the sun being 400x larger but also 400x farther away.
By the time the sun's rays get to the earth from those distances, the sun's ray's are a small fraction of a degree off completely parallel with one another. So this picture here is a total lie. Nevertheless, I suspect that the scale of the moon is a bit off as well, given the alleged distances involved. So I think a real objective study of the matter needs to be performed. Yet why are such studies lacking? It's because every operates on the ASSUMPTION (begging the question) that the heliocentric model is correct, so they're more about coming up with narratives to explain away the various phenomena that seem to run counter to the globe model rather than attempting to look at them objectively.