Functions only working once/ for only one id at a time

I’m currently creating a Simple Pomodoro timer. I have a function to start the countdown, and it only works on the first 25 minute timer. When I use it for the others (break times), it does not work. Not only the startCountdown() function but also the functions which activates an icon.

HTML:

   <div id="break" style="display: none">
            <div id="outerBorder">
                <div id="bodybg"> 
                    <div class="absButtonBreak">
                            <img id="fiveMin" src="Objects/buttonsBreak/5m.png" onclick="showPage('forFive')">
                        <img id="ftnMin" src="Objects/buttonsBreak/15m.png" onclick="showPage('forFifteen')">
                        <img id="thrtMin" src="Objects/buttonsBreak/30m.png" onclick="showPage('forTwenty')">
                    </div>
                        <img src="Objects/Back.png" class="buttonBack" onclick="showPage('pg1')">
                    </div>
                </div>
            </div>
        </div>
<!-- There's a page called "break" where "forFive" is in-->
    <div id="forFive" style="display: none;">
        <div id="outerBorder">
            <div id="bodybg">
                <img id="catBus" src="Objects/Icon_CatBus/catBus1.png" class="icon_CB">
                <div id="timer">
                    <img id="minTens" class="digit">
                    <img id="minOnes" class="digit">
                    <span>:</span>
                    <img id="secTens" class="digit">
                    <img id="secOnes" class="digit">
                </div>
                <div class="buttonsTimer">
                    <img id="strtBtn5" src="Objects/Strt.png" class="buttonStart">
                    <img id="stop" src="Objects/Stop.png" class="buttonStop" onclick="showPage('break')">
                </div>
                <img id="back" src="Objects/Back.png" class="buttonBack" >
            </div>
        </div>
    </div>`

JS:

let timer;
let mins = 0;
let secs = 0;

function startCountdown(m, s) {
  clearInterval(timer);
  mins = m;
  secs = s;

  setDigit("minTens", Math.floor(mins / 10));
  setDigit("minOnes", mins % 10);
  setDigit("secTens", Math.floor(secs / 10));
  setDigit("secOnes", secs % 10);

  timer = setInterval (() => {
    if (secs === 0 && mins === 0) {
      clearInterval(timer);
      const icon = document.getElementById("catBus");
      icon.src = "Objects/Icon_CatBus/catBus1.png";
    } else {
      if (secs === 0) {
        mins--;
        secs = 59;
      } else {
        secs--;
      }
      setDigit("minTens", Math.floor(mins / 10));
      setDigit("minOnes", mins % 10);
      setDigit("secTens", Math.floor(secs / 10));
      setDigit("secOnes", secs % 10);
    }
  }, 1000);
}

//some other things

  

This is what I did in order to categorize it by time:

  document.getElementById("strtBtn25").addEventListener("click", () => {
    startCountdown(25,0);
    activateIconCB();
  })

  document.getElementById("strtBtn5").addEventListener("click", () => {
    startCountdown(5,0);
    activateIconCB();
  })

How do I make the functions to work for other divs/ids or whatever you call them? (trying to make strtBtn5 also work like strtBtn25)