Why doesn't my 7 segment update every second like in the program?
This is the code that fixed the issue:

  #include &lt;SevSeg.h&gt;
  SevSeg sevseg;

  void setup() {
    byte numDigits = 4;
    byte digitPins[] = {5, 4, 3, 2};
    byte segmentPins[] = {13, 12, 11, 10, 9, 8, 7, 6};
    sevseg.begin(COMMON_CATHODE, numDigits, digitPins, segmentPins);
    sevseg.setBrightness(50);
    sevseg.setNumber(0000, -1);
  }

  void loop() {
    unsigned long timerGlobal = millis();
    sevseg.setNumber(timerGlobal/1000, -1);
    sevseg.refreshDisplay();
  }


In this, no delays are needed. millis is divided by 1000 and the integer second is drawn on the display. Proved to be much easier than I previously thought.