HC-12 problem with reading momentarily strings

I'm new here, so I hope my question is not naive. I'm using Arduino mega connected with a pulse sensor and a GPS (and other things that are not related to our problem), pulse sensor and GPS data are sent momentarily through HC-12 433 Mhz module to a receiver arduino uno that is only receiving data through HC-12 as well

for processing reasons, I send GPS data with a "G" prefix .. e.g "G11.00,7.45". and pulse data consist of those three: "S100" "Q97" "B22" // 100,97,22 are just examples, and each one is sent alone

for some reason, the receiver Arduino uno, is reading the data in it's ASCII decimal form and also separate it in a new line.

I can not use Serial.readString(), because it only print data after terminating the Serial communication and I need it momentarily, I tried to configure Serial.setTimeout() , but I couldn't manage to find a suitable time for all data.

please check my code and help me solve my problem, thank you

#include <Adafruit_GPS.h>
// what's the name of the hardware serial port?
#define GPSSerial Serial1
// Connect to the GPS on the hardware port
Adafruit_GPS GPS(&GPSSerial);

String gpsData="";
String pulseData="";
#include <SoftwareSerial.h>
SoftwareSerial mySerial(12, 13); // RX, TX  HC-12
uint32_t timer = millis();
void setup(){  // I think there is no problem here
  Serial.begin(115200);             // we agree to talk fast!
  mySerial.begin(115200);
  interruptSetup();   // initialize timers to read pulse sensor and GPS at fixed intervals
      GPS.begin(9600);
  delay(100);
  GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);
  delay(100);
  GPS.sendCommand(PMTK_SET_NMEA_UPDATE_100_MILLIHERTZ);
  GPS.sendCommand(PGCMD_ANTENNA);
  delay(1000);
  GPSSerial.println(PMTK_Q_RELEASE);
}
void loop(){
 // that show me if there is a new data, you can skip it
 if (GPS.newNMEAreceived()) {
    // a tricky thing here is if we print the NMEA sentence, or data
    // we end up not listening and catching other sentences!
    // so be very wary if using OUTPUT_ALLDATA and trying to print out data
    GPS.lastNMEA(); // this also sets the newNMEAreceived() flag to false
    if (!GPS.parse(GPS.lastNMEA())) // this also sets the newNMEAreceived() flag to false
      return; // we can fail to parse a sentence in which case we should just wait for another
  }

  //
if (millis() - timer > 10000) { // send GPS data every 10 seconds
    timer = millis(); // reset the timer
    if (GPS.fix) {
      
      gpsData.concat('G');
      x=GPS.latitude/100;
      gpsData.concat(x);  // I also tried String(x)
      gpsData.concat(',');
      y=GPS.longitude/100;
      gpsData.concat(y);  // I also tried String(y)
      mySerial.println(gpsData);  // here I send GPS  data through HC-12 to the receiver Arduino uno
      gpsData=""; // reset 
    }
}
  sendDataToProcessing('S', Signal);     // send Processing the raw Pulse Sensor data
  if (QS == true){                       // Quantified Self flag is true when arduino finds a heartbeat
       
        sendDataToProcessing('B',BPM);   // send heart rate with a 'B' prefix
        sendDataToProcessing('Q',IBI);   // send time between beats with a 'Q' prefix
        QS = false;                      // reset the Quantified Self flag for next time    

  }
  delay(50);
}
void sendDataToProcessing(char symbol, int data ){
 // here I send pulse data through HC-12 to the receiver Arduino uno, and then process it using processing in the receiver arduino
    pulseData.concat(symbol);
    pulseData.concat(data);
    Serial.println(pulseData);  // just for debugging and it was okay 
    mySerial.println(pulseData);
    pulseData=""; //reset
  }

interruptSetup() {
// no need to read it, it is just some timer 1 and timer 2 initialization and their ISR, timer 1 read pulse sensor every 2 milliseconds (yeah fast but I guess mega could handle it),and do some calculations to find S, Q, and B.
and timer 2 read GPS coming sentences.
}

the receiver code

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);  //I will connect HC-12 directly to pin 0,1
}

void loop() {
  // put your main code here, to run repeatedly:
while(Serial.available() >1){
  String input = String (Serial.read());//read string , I need to cast it into String because data comes in ASCII
// I also tried int input = Serial.read() ; //same thing happened
    Serial.println(input);
}
}

waiting for your response.

###edit### to conclude the problem is that I want to receive data in the uno as it has been sent from the mega

e.g: I receive sI guess the ascii of the letter and the number also changes to some number

send  |  recive
S490  | 52
        53 
Q252  | 10
        83
B160  | 48
        13

I used Serial.write(Serial.read()) instead of Serial.println, and it worked, does someone know why?