But then you "fill up all the photon slots" too (not literally because they are not fermions, but they do spontaneously convert back into things like electrons at that density) and you can work around the Pauli exclusion principle by stacking your electrons at higher and higher energy levels.

Pauli exclusion isn't an impenetrable force field - as you say, it's just often more favourable to do something else than to work around it. Consider an iron atom with however many electrons though - all those orbitals except the inner one are electrons working around Pauli.

I'm not a physicist either.

Pauli exclusion is a QM thing. Black holes are a GR thing. Famously, we don’t know how to mix the two.

Pauli Exclusion is just another “force” that can be overridden. Nature isn’t a list of rules