My experience is that one mess is pretty straightforward, what is debilitating is interconnected messes. System A is the highest priority fix and we want to in

My experience is that one mess is pretty straightforward, what is debilitating is interconnected messes. System A is the highest priority fix and we want to incorporate parts of system B into system A (they never should have been in B) but if we move them to system A, the other parts of system B will break (so we need to fix those) and then additionally system C will no longer work so we need to fix that, and on and on…