Why does my TFT keep turning white after moments?

Question

Alright, seems there is something wrong I am doing that I don't understand. Before I start explaining, my question is different than this white screen question.

First of all my TFT ST7735 is working very well with the below code, let's name it, code part 1:

#define USE_ARDUINO_INTERRUPTS true    // Set-up low-level interrupts for most acurate BPM math.
#include <PulseSensorPlayground.h>     // Includes the PulseSensorPlayground Library.   
#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include <SPI.h>
#include <SD.h>

  #define TFT_CS        10
  #define TFT_RST        9 // Or set to -1 and connect to Arduino RESET pin
  #define TFT_DC         8

#define TFT_MOSI 11  // Data out
#define TFT_SCLK 13  // Clock out

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);
float p = 3.1415926;
int Variable1;
int ledState = HIGH;  
//  Variables
int PulseWire = 0;       // PulseSensor PURPLE WIRE connected to ANALOG PIN 0
int myBPM = 0;
const int LED13 = 13;          // The on-board Arduino LED, close to PIN 13.
int Threshold = 550;           // Determine which Signal to "count as a beat" and which to ignore.
// constants won't change:
const long interval = 1000;   

unsigned long previousMillis = 0;
static uint32_t tsLastReport = 0;  

void setup(void) {
  Serial.begin(9600); 

  Serial.print(F("Hello! ST77xx TFT Test"));

#ifdef ADAFRUIT_HALLOWING

  tft.initR(INITR_HALLOWING);        // Initialize HalloWing-oriented screen
  pinMode(TFT_BACKLIGHT, OUTPUT);
  digitalWrite(TFT_BACKLIGHT, HIGH); // Backlight on
#else

  tft.initR(INITR_144GREENTAB); // Init ST7735R chip, green tab

#endif

  Serial.println(F("Initialized"));

  uint16_t time = millis();
  tft.fillScreen(ST77XX_BLACK);
  time = millis() - time;

  Serial.println(time, DEC);
  delay(500);

  Serial.println("done");
  delay(1000);


}

void loop() {



  testdrawtext(" BPM: ", ST77XX_WHITE);
  tft.setTextColor(ST77XX_RED);  
  tft.setTextSize(2); 

  int sensorValue = analogRead(A0);

  tft.print(sensorValue); 
    delay(300);
  tft.fillScreen(ST77XX_BLACK);





}


void testdrawtext(char *text, uint16_t color) {
   tft.setCursor(0, 0);
 tft.fillScreen(ST77XX_BLACK);


  tft.setCursor(0, 0);
  //  tft.setCursor(10, 40);
  tft.setTextSize(2);
 // tft.setTextColor(color);
  tft.setTextColor(ST7735_YELLOW);
  tft.setTextWrap(true);
  tft.print(text);
   delay(200);
}

Here is the video for Part 1 running very good with a random analog number.

Secondly, I have a simple Heart Beat circuit and it is working very well when I apply this getting_BPM_to_Monitor code into it. I don't have a photo for it but trust me it is working good so please, when I do attach the schematic don't focus too much on the hardware side, it might not be very perfectly stable but it is working fine for me.

Now, is the magic when I combine the Heart Beat which is getting_BPM_to_Monitor & TFT ST7735 circuit things don't seem alright and I think a code with a video is better explaining the issue than me. The below code, let's name it, code part 2:

#define USE_ARDUINO_INTERRUPTS true    // Set-up low-level interrupts for most acurate BPM math.
#include <PulseSensorPlayground.h>     // Includes the PulseSensorPlayground Library.   
#include <Adafruit_GFX.h>    // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include <SPI.h>
#include <SD.h>

  #define TFT_CS        10
  #define TFT_RST        9 // Or set to -1 and connect to Arduino RESET pin
  #define TFT_DC         8
.
#define TFT_MOSI 11  // Data out
#define TFT_SCLK 13  // Clock out

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);
float p = 3.1415926;
int Variable1;
int ledState = HIGH;  
//  Variables
int PulseWire = 0;       // PulseSensor PURPLE WIRE connected to ANALOG PIN 0
const int LED13 = 13;          // The on-board Arduino LED, close to PIN 13.
int Threshold = 550;           // Determine which Signal to "count as a beat" and which to ignore.
int myBPM = 0;
PulseSensorPlayground pulseSensor;  // Creates an instance of the PulseSensorPlayground object called "pulseSensor"

static uint32_t tsLastReport = 0;  

void setup(void) {
  Serial.begin(9600);
 // .  PulseWire = 3;
  pulseSensor.analogInput(PulseWire);   
  pulseSensor.blinkOnPulse(LED13);       //auto-magically blink Arduino's LED with heartbeat.
  pulseSensor.setThreshold(Threshold);   
  pulseSensor.begin();

  Serial.print(F("Hello! ST77xx TFT Test"));

#ifdef ADAFRUIT_HALLOWING

  tft.initR(INITR_HALLOWING);        // Initialize HalloWing-oriented screen
  pinMode(TFT_BACKLIGHT, OUTPUT);
  digitalWrite(TFT_BACKLIGHT, HIGH); // Backlight on
#else
  // Use this initializer if using a 1.8" TFT screen:
 // tft.initR(INITR_BLACKTAB);      // Init ST7735S chip, black tab

  // OR use this initializer (uncomment) if using a 1.44" TFT:
  tft.initR(INITR_144GREENTAB); // Init ST7735R chip, green tab

  // OR use this initializer (uncomment) if using a 0.96" 180x60 TFT:
  //tft.initR(INITR_MINI160x80);  // Init ST7735S mini display

  // OR use this initializer (uncomment) if using a 1.54" 240x240 TFT:
  //tft.init(240, 240);           // Init ST7789 240x240
#endif

  Serial.println(F("Initialized"));

  uint16_t time = millis();
  tft.fillScreen(ST77XX_BLACK);
  time = millis() - time;

  Serial.println(time, DEC);
  delay(500);

  Serial.println("done");
  delay(1000);

  Variable1 = 90;

}

void loop() {



  testdrawtext(" BPM: ", ST77XX_WHITE);
  tft.setTextColor(ST77XX_RED);  
  tft.setTextSize(3); 

  myBPM = pulseSensor.getBeatsPerMinute();   
if (pulseSensor.sawStartOfBeat()) {                            
}

  tft.print(myBPM); 
      delay(300);
  tft.fillScreen(ST77XX_BLACK);





}

void testdrawtext(char *text, uint16_t color) {
   tft.setCursor(0, 0);
 tft.fillScreen(ST77XX_BLACK);


  tft.setCursor(0, 0);
  //  tft.setCursor(10, 40);
  tft.setTextSize(2);
 // tft.setTextColor(color);
  tft.setTextColor(ST7735_YELLOW);
  tft.setTextWrap(true);
  tft.print(text);
   delay(200);
}

Here is the video or this video for Part 2

Lastly, I provided the schematic for more reasoning opinion and it was provided by Easyeda.com and you have to have an account to view my schematic

Things I have tried...

• I have modified TFT pins since Gtting_BPM_to_Monitor uses Timer1 & Timer2
• I have added/remove a lot of delays
• I have insertednoInterrupts(); and interrupts();

Edit 1 : Here is a PNG of the schematic if and hopefully, it is clear enough.