esp32 modbus rtu hex to float convert - c++

Question

I can send a request and get an response (modbus RTU frame) from the device (flow meter) but I cannot convert hex to float. Otherwise everything works fine and the way I want it. Does anyone know how to improve it in a simple way?
void loop() {
const char msg_reguest[] = {0x01, 0x04, 0x00, 0x08, 0x00, 0x02, 0xf0, 0x09};
delay(200);
int i;
int len=8;
Serial.println("WYSŁANA RAMKA");
for(i = 0 ; i < len ; i++){
Serial2.write(msg_reguest[i]);
Serial.print("[");
Serial.print(i);
Serial.print("]");
Serial.print("=");
Serial.print("Ox");
Serial.print(String(msg_reguest[i], HEX));
Serial.print(" ");
}
len = 0;
Serial.println();
Serial.println();
int a = 0;
while(Serial2.available())
{
ByteArray[a] = Serial2.read();
a++;
}
int b = 0;
String registros;
Serial.println("ODEBRANA RAMKA");
for(b = 3 ; b < a-2 ; b++){
Serial.print("[");
Serial.print(b);
Serial.print("]");
Serial.print("=");
Serial.print("Ox");
registros =String(ByteArray[b], HEX);
Serial.print(registros);
Serial.print(" ");
}
byte hexArray[] = "registros";
float value;
memcpy(&value, hexArray, sizeof(hexArray));
Serial.println(value);
}
the point is that I have an esp32, TTL rs485 and a flow meter with rs485. I download a frame each time with a different data value. I display the frame with the flow data in the serial monitor in the form of HEX. Esp32 are little Endian, so I want to change the order of numbers and write a function that will automatically convert to float. In the above code I try to do it but it doesn't work