High Resolution Gyro Question

Thank you for the continued help J-M-L !! Really appreciate you taking the time to work with me on this.
here is my attempt at integrating what you have suggested.
Not sure if this was what was intended..

I also got a warning that the Serial.readBytes was expecting a Char or Byte for the buffer type so I changed it to a Byte rather then an Int.

#include <LiquidCrystal.h>
LiquidCrystal lcd(10, 9, 8, 7, 6, 5);       // put your pin numbers here

byte index = 0;
byte DMM_ARRAY[6];   // Where to store the Bytes read
byte c;
//char SETUP = 0x65;
int n = 0;
float previousValue = 0;
float currentValue = 0;
uint32_t t = 0;   // Time record was received '2', '3', '4', '5', '6', '7', '8', '9', ' ', 'L'};


void setup() {
  pinMode(11, OUTPUT);    // LCD CONTRAST PIN
  pinMode(2, OUTPUT);     // Clear To Send PIN
  pinMode(3, OUTPUT);     // Request Sample PIN
  analogWrite(11, 50);    //LCD CONTRAST AMOUNT
  Serial.begin(1000000);
  lcd.begin(16, 2);
  lcd.print("GG1320AN21 TEST");
  lcd.clear();
}


bool Get_data() {
  bool success = (Serial.available() >= 6);
  if (success) Serial.readBytes(DMM_ARRAY, 6);
  return success;
}

void loop() {

float deltaTheta;
static unsigned long previousMicros=0;
unsigned long currentMicros = micros();    // you could do this with millis() too, depends on the precision you want

  if (currentMicros - previousMicros >= 1000000ul) { // 1s in µs
    unsigned long deltaT = currentMicros - previousMicros; // that will be give or take 1s
    digitalWrite(2, HIGH);  // CTS Open
    digitalWrite(3, HIGH);  // RS
    delayMicroseconds( 50 );
    digitalWrite(3, LOW);  //RS

      if (Get_data()) { //Read the Serial bytes coming in
      currentValue = DMM_ARRAY[2];
      delayMicroseconds( 200 );
      digitalWrite(2, LOW);  // CTS Close
     
      deltaTheta =((previousValue - currentValue)* 1.113065); // count * 1.113065   ARC SEC / SEC
      
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print(deltaTheta / (deltaT / 1000000)); //3 decimal place values
      lcd.print(" ");
      
      lcd.setCursor(0, 1);
      lcd.print( DMM_ARRAY[2]);// Print btye 3 (LSB)
      lcd.print(" ");
      
      }

  previousMicros = currentMicros;
  previousValue = currentValue;
  
  }

}

/*
void  Get_data() {

if (Serial.available() >= 6) {
    for (int i = 0; i < 6; i++) {
      DMM_ARRAY[i] = Serial.read();
    }
  }
}
*/