GSAP timeline to speedup / slowdown any animations on it

Thank you very much Math,
I have a conflict with the background audio help, since also within my functionalities I added to be able to speed up the voiceover audio (https://community.articulate.com/discussions/articulate-storyline/can-you-speed-up-the-player-in-articulate-360?page=3), however, when I do this, it also speeds up my background audio.
Can you help me to find the solution in the java so that it does not take the background audio speed.

https://community.articulate.com/discussions/articulate-storyline/continuous-playing-background-music-over-all-slides-in-storyline360

My code:

speed up audio

var allAudios = document.getElementsByTagName("audio");
for (var i = 0; i < allAudios.length; i++) {
   allAudios[i].playbackRate = 1.25;
}

slow down audio

var allAudios = document.getElementsByTagName("audio");
for (var i = 0; i < allAudios.length; i++) {
   allAudios[i].playbackRate = 0.5;
}

Audio background

//load the scripts dynamically into the head of the document

function add_line() {
    var line = document.createElement("audio");
    var head=document.getElementsByTagName('body')[0];
    line.type = "audio/mp3";
    line.src="";
    line.id="bgSong" ;
    line.autoplay = true;
    line.loop = true;
    head.appendChild(line);
}

//but we only want to add these once!
if(document.getElementById('bgSong')==null){
    add_line();
var audio = document.getElementById('bgSong');
audio.volume = 0.5;
}

play audio background

var audio = document.getElementById('bgSong');
audio.src="story_content/external_files/MusicaDiversidad.mp3";
audio.load();
audio.play();

I hope you can help me

Thanks