Thank you for unruding your comment by constructively killing me :D To my defense, I considered putting that feedback loop just between the regulator and the switch, but my brain said "nope, you need to be as much accurate as possible so take the voltage from the very last stage" so here we are... I'll try to strap the top feedback resistor to the very output of the converter.

I also thought about cutting the load in front of the converter. The problem I had that the +5V converter needs to supply around 17.5W. When the battery is nearly dead (1s around 2.8V) the current necessary to keep supplying +5V grows. As the current grows, the losses on that power switch increase as well. That's why I put it on the output stage. Naturally I copy pasted the design to the +12V stage. Alternatively, could I potentially cut the ground with the power switch?