Does the da vinci use a regular endstop? min or max direction? For z min endstop you normally calibrate the endstop or bed to trigger exactly when bed is in contact with nozzle.
#define ENDSTOP_Z_BACK_MOVE 2should be 0. You can set it to a value to go up afterwards, but it will then always hit and push the bed during homing, so better to adjust the endstop correctly.