Failing Conf

wdio.conf.js

exports.config = {
  // Other options
  
  before() {
    browser.addCommand('displayText', function (text, duration = 3000) {
      const textElId = `text-el-${Math.floor(Math.random() * 10000)}`

      this.execute(function (id, text, duration) {
          var textContainer = document.createElement("div");
          textContainer.id = id;
          textContainer.style.display = "flex";
          textContainer.style.alignItems = "center";
          textContainer.style.justifyContent = "center";
          textContainer.style.position = "fixed";
          textContainer.style.top = 0;
          textContainer.style.left = 0;
          textContainer.style.width = "100%";
          textContainer.style.height = "100%";
          textContainer.style.zIndex = 16000005;
          textContainer.style.background = "hsla(0, 0%, 0%, 0.85)";
          textContainer.style.color = "hsl(0, 100%, 100%)";
          textContainer.style.fontSize = "5vh";
          textContainer.style.fontWeight = "bold";
          textContainer.style.opacity = 1;
          textContainer.style.transition = "opacity 400ms linear";
          textContainer.appendChild(document.createTextNode(text));
          document.body.appendChild(textContainer);

          setTimeout(function () {
              textContainer.style.opacity = 0;
              setTimeout(function () {
                  textContainer.parentNode.removeChild(textContainer)
              }, 400);
          }, duration);
      }, textElId,  text, duration)

      this.waitUntil(() => !this.isExisting(`#${textElId}`))
  })
  },
  
  beforeTest(test) {
    try {
        browser.displayText(test.fullTitle)
    } catch (e) {
        // Displaying the title card should never cause a test to fail, so
        // we'll just eat any errors it may cause.
    }
  }
}

think this is where you have mistake, comment it and isolate it