I understand, but Schrodinger himself came up with the cat thought experiment to demonstrate that he felt something was obviously wrong. A version of the Copenhagen interpretation would just say the wave equation is a useful tool for predicting experimental outcomes. We can't say what's really happening when we're not observing. So you don't need to add anything, you just give up on saying what's real. Which seems defeatist or anti-realist, but then one can always hold out hope for better experiments to one day show us what is really going on.

As for parsimonious interpretations, what does superdeterminism add?