LCD only white squares

Hello,
I've seen that there have been posts on this topic before but I haven't found a fitting solution, this is the 2nd LCD I have connected to an Arduino and the first one worked the way I did it, the difference is that the other one that works is 16x1 and green, and the one now is 16x2 and blue but I believe it should be the same for controlling it. I hope that someone can help me understand and fix my problem.
Thank you!

Here's my code:

#include <LiquidCrystal.h>

#define LCD_PWR 2
LiquidCrystal lcd(3, 4, 5, 6, 7, 8);

void setup() {
  pinMode(LCD_PWR, OUTPUT);
  digitalWrite(LCD_PWR, HIGH);

}

void loop() {
  lcd.begin(16, 2);
  lcd.print("hello, world!");
  delay(1000);
}

Pictures:

Can you post a schematic?

I don't see a contrast adjustment pot.

This should be in setup(), not loop().

Not sure that putting it in loop() would cause your problem, but worth trying.

The LCD RW pin (pin 5) must be tied to ground.

Tie the LCD Vo pin (contrast, pin 3) needs to be tied to ground through a resistor or potentiometer. For testing connect Vo directly to ground.

Are your LCD backlight LED pins connected ?

Thank you!
This was the problem I put a 4.7k resistor between GND and pin 3 and I was able to see my text.

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