TX RX Defaults in ESP32 C3 Xiao with SDA SCL

I have two sensors Air Quality PMS5003 (RX/TX 20/21) and Pressure Sensor xgzp6897d (default i assume is SCL/SDA D7/D6 or GPIO7/6) connected to XIao ESP32C3. When I run the code as shown here it seems not to get to the pressure readings from the 7/6 as device is not responding. SO its not finding the pressure sensor but does not move on to get the air quality sensor readings. When i remove the pressure sensor part from the code it does give the air quality readings. Is the sdl/sca pin interfereing with rx/tx? I assume the scl/sda pins are set default, am i right? Is there a need to define the SCL/SDA pins in the code then how do i define them?
The code works fine with ESP32 Wroom.

#include <XGZP6897D.h>

#define K 8192 // see table above for the correct value for your sensor, according to the sensitivity.
XGZP6897D mysensor(K);
float pressure, temperature;

#include <SoftwareSerial.h>
SoftwareSerial pmsSerial(20, 21);
 
void setup() {
  // our debugging output
  Serial.begin(115200);
   // sensor baud rate is 9600
  pmsSerial.begin(115200);
  
  while (!mysensor.begin())  // initialize and check the device
  {
    Serial.println("Device not responding.");
    delay(500);
  }

  
}
 
struct pms5003data {
  uint16_t framelen;
  uint16_t pm10_standard, pm25_standard, pm100_standard;
  uint16_t pm10_env, pm25_env, pm100_env;
  uint16_t particles_03um, particles_05um, particles_10um, particles_25um, particles_50um, particles_100um;
  uint16_t unused;
  uint16_t checksum;
};
 
struct pms5003data data;
    
void loop() {
  pmsSerial.begin(115200);
  if (readPMSdata(&pmsSerial)) {
    Serial.println(data.pm10_standard);
    Serial.println(data.pm25_standard);
    Serial.println(data.pm100_standard);
    Serial.println(data.particles_03um);                                                                
    Serial.println(data.particles_05um);
    Serial.println(data.particles_10um);
    Serial.println(data.particles_25um);
    Serial.println(data.particles_50um);
    Serial.println(data.particles_100um);

  }

     if (mysensor.readSensor(temperature, pressure))
      {
          Serial.println(temperature);
          Serial.println(pressure); 
          Serial.println();
        }
        else Serial.println("Reading fails. Timeout ??");
        delay(100);

}

 
boolean readPMSdata(Stream *s) {
  if (! s->available()) {
    return false;
  }
  
  // Read a byte at a time until we get to the special '0x42' start-byte
  if (s->peek() != 0x42) {
    s->read();
    return false;
  }
 
  // Now read all 32 bytes
  if (s->available() < 32) {
    return false;
  }
    
  uint8_t buffer[32];    
  uint16_t sum = 0;
  s->readBytes(buffer, 32);
 
  // get checksum ready
  for (uint8_t i=0; i<30; i++) {
    sum += buffer[i];
  }
 
  /* debugging
  for (uint8_t i=2; i<32; i++) {
    Serial.print("0x"); Serial.print(buffer[i], HEX); Serial.print(", ");
  }
  Serial.println();
  */
  
  // The data comes in endian'd, this solves it so it works on all platforms
  uint16_t buffer_u16[15];
  for (uint8_t i=0; i<15; i++) {
    buffer_u16[i] = buffer[2 + i*2 + 1];
    buffer_u16[i] += (buffer[2 + i*2] << 8);
  }
 
  // put it into a nice struct :)
  memcpy((void *)&data, (void *)buffer_u16, 30);
 
  if (sum != data.checksum) {
    Serial.println("Checksum failure");
    return false;
  }
  // success!
  return true;
}

I think one of your sensors is IIC… you would need wire library and some other stuff

Thanks. THe pms5003 transmits UART as TX RX and is connected to Xiao ESP32C3 at 21/20 thats why should to be declared in SoftwareSerial . The perssure sensor xgxp6897D is I2C and in most boards its defined as default but I guess the default declaration in Wire (used in the library xgzp6897D) is different from the default SDA/SCL 6/7 shown by SeeedStudio. What is the workable SDA/SCL is what I cannot figure out. So i need help for this.

Is the xgxp6897D power supply pin connected to 5V? If so, try connecting it to 3.3V.
Use “I2C Scanner” to see if the address of the xgxp6897D is detected.
What is the link to the actual sensor you are using? Is it a stand-alone module? Or is it a breakout board?