I am running this code against this circuit.

#include <Arduino.h>

const int _selectPins[3] = {36, 37, 38};    // S0~2, S1~3, S2~4
const int _dataInput = 4;                   // Connect common (Z) to A0 (analog input)

unsigned long previousMillis = 0; 
const long interval = 1000;

void selectMuxPin(byte pin);

void setup() 
{
  Serial.begin(115200);
  for (int i=0; i<3; i++)
  {
    pinMode(_selectPins[i], OUTPUT);
    digitalWrite(_selectPins[i], HIGH);
  }

  pinMode(_dataInput, INPUT);

  selectMuxPin(0);
}

float GetVoltage(int _batteryVoltageRawValue) {  // Calculate Voltage Sensor Value from Battery
    float R1     = 30000.0;
    float R2     = 7500.0;
    float vout   = (float(_batteryVoltageRawValue) * 3.3) / 4096.0;
    // float result = vout / (R2 / (R1 + R2));
  float result = vout*(R1+R2)/R2;

  // Calibration 
    result       = result * 1.01595;
  return result;
}

void loop() 
{
  unsigned long currentMillis = millis();
  int rawVoltValue = analogRead(_dataInput);
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    Serial.print("Volt raw value : "); Serial.println(rawVoltValue);
    Serial.print("Volt value : "); Serial.print(GetVoltage(rawVoltValue)); Serial.println("V");
  }
}

// The selectMuxPin function sets the S0, S1, and S2 pins
// accordingly, given a pin from 0-7.
void selectMuxPin(byte pin)
{
    for (int i=0; i<3; i++)
    {
        if (pin & (1<<i)) {
            digitalWrite(_selectPins[i], HIGH);
        } else {
            digitalWrite(_selectPins[i], LOW);
        }
    }
}

circuit schema

When i plug/unplug the battery, the ESP32 stop running.

If i put a voltmeter between +5v and GND, it does not happen.

Tried to add a 10K pull down resistor on Y0, but it seems to act like a voltage divider bridge.

What can i do to found the issue ?
thank you.