Here it is. I don't think the circuit (PCB) is the problem, it works with a different board and I have done a new one during these problems just to be sure.
If you would wander: I measured the stepdown and it contstantly outputs 5.06V.
So have you made up a custom PCB with sockets for the stepper drivers, switches etc?
What happens when you remove one of the damages ESP32 modules from the PCB, does it still not work?
Can you also check the 3.3V pin of one of the damaged ESP32 modules and see what it is putting out when the module is powered up on the PCB?