Question Raspberry Pi Pico communication with simtools

Hello,
First of all, I am new to programming. I am trying to write code (in C++) that will allow Pi Pico to receive data over usb/uart (I found usb serial connection not working quite right so I am using usb to ttl adapter for communication) from SimTools. The problem I have is when I test my code manually by sending values over terminal (putty) it works just fine, it reads numbers that I wrote and converts them into integers and echoes it back, but once I try receiving data from SimTools, I see no data being sent and no data echoes back (I am using to usb to ttl converters to see what's happening). I configured simtools to send decimal data so its easier (atleast for me) to use it.
For reading the data I am using non blocking version of getchar_timeout_us(0) but I am wondering if thats the problem and I should use something else. If I send data simtools data from one usb to ttl adapter to another it works just fine.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "pico/stdlib.h"

#define ENDSTDIN    255
#define CR        13

int main() {
    stdio_init_all();

    bool onoff = 0;
    const uint LED_PIN = 25;
    char strg[24]; // how much characters are expected minus one
    char pirmas[5];
    char antras[5];
    char trecias[5];
    char ketvirtas[5];
    char penktas[5];
    char chr;
    char narys;
    int lp = 0;
    int x = 0;
    int y = 0;
    int z = 0;
    int xx=0;
    int yy=0;

    memset(strg, 0, sizeof(strg));

    gpio_init(LED_PIN);
    gpio_set_dir(LED_PIN, GPIO_OUT);

    while (true) {
        chr = getchar_timeout_us(0);
        while(chr != ENDSTDIN)
        {   
            strg[lp++] = chr;          //start collecting input char one by one
            if(chr == CR || lp == (sizeof(strg) - 1)) //checks if all data is collected
            {
                memcpy(pirmas, strg, 4 );
                memcpy(antras, &strg[4], 4 );
                memcpy(trecias, &strg[8], 4 );
                memcpy(ketvirtas, &strg[12], 4 );
                memcpy(penktas, &strg[16], 4 );
                narys = strg[20];
                printf("You wrote - %c\n", narys);
                strg[lp] = 0;    //terminate string
                x =  atoi (pirmas);
                y =  atoi (antras);
                z =  atoi (trecias);
                xx =  atoi (ketvirtas);
                yy =  atoi (penktas);
                printf("You wrote - %d\n", x);
                printf("You wrote - %d\n", y);
                printf("You wrote - %d\n", z);
                printf("You wrote - %d\n", xx);
                printf("You wrote - %d\n", yy);
                //memset(strg, 0, sizeof(strg));
                lp = 0;        //reset string buffer pointer
                break;
            }
            chr = getchar_timeout_us(0);
            }

        gpio_put(LED_PIN, onoff);
        onoff = !onoff;
        sleep_ms(1);
    }

    return 0;

In my case I am trying to read data for five axis.

Hey, thanks for reply, I already sorted the problem out, now it works as intended.