Fact is that scientists know nothing about stars and supernovae for sure.
There speaks somebody who hasn't got a clue as to either the current state of astronomy or the current state of stellar thermodynamics.
Stars and supernovae have the advantage of being great big lab experiments that obligingly pump out vast amounts of data for us to study. We know more about them, objectively, than we do about the ground 50km below our feet. A lot of their nuclear reactions have been confirmed on Earth. Even in the early 1970s with the primitive computers of the day, astrophysicists were modelling novas and supernovas. (I know because the guy given the shitty job of trying to teach me thermodynamics was one of them. Sorry.)
The fact that scientists don't know a lot about an extremely rare type of event that has not previously been encountered and is only now being investigated could be described as "normal for science".