Add interactivity to a Lottie-SVG element by JS

Lottie in Web
1

Hello
I would like to add interactivity on Lottie SVG elements by js.

I named the layer with the element in AE #test so that I can access it by getElementById.

Unfortunately, it doesn’t work. btTest is null.
Thank you a lot for any help!

Here is the lottie file:
https://www.cognitographik.ch/qualitaet-lottie2/test.html

Here is the code:

<button onclick="buttonFunction()">Click Me</button>

<lottie-player
  autoplay
  loop="false"
  mode="normal"
  id="firstLottie"
  src="https://www.cognitographik.ch/qualitaet-lottie2/data.json"
  background="transparent"
  speed="1"
  style="width: 50%; height: 50%"
></lottie-player>

<script>
  function buttonFunction() {
    let btTest = document.getElementById("test");
    btTest.style.cursor = "pointer";
  }

</script>