My variable is scoped and I need it to be global

Question

Hi so this I am this basic newbie asking for help after looking by my self a fair amount of hours.

I am toy-programming a game where I use the smartphone orientation to trigger events. My problem is that I cannot get a variable value, which seems to be out of reach. The game is working pretty well if I send params for a function to one another but if I need to change the global variable so I can use it easily.

1. It seems my variable is scoped and I do not understand how I can help it.
2. In the sample below, how can I make the beta variable a global one?
3. Is the variable scoped because of the if statement, the => or .then?

//The variable pression is the one I need to be global
let beta, gamma, pression=0, gameover=false, audio_source;

//displaying banner to authorize DeviceOrientationEvent on mobile
function bannerAuthorisation() {
   if (window.DeviceOrientationEvent && typeof window.DeviceOrientationEvent.requestPermission === 'function'){
      const banner = document.createElement('div');
      banner.innerHTML = `<div id="autorisation" style="z-index: 1; position: absolute; width: 100%; background-color:#000; color: #fff" onclick="clickRequestDeviceOrientationEvent();"><p style="padding: 10px">Cliquez ici pour autoriser l'accès à votre capteur de mouvements.</p></div>`;
      document.querySelector('body').appendChild(banner)
    } else {
      alert("Sorry you cannot play");
    }
}

//If permission to play with DeviceOrientationEvent is granted, then I fetch beta and gamma
function clickRequestDeviceOrientationEvent() {
  window.DeviceOrientationEvent.requestPermission()
      .then(response => {
        if (response === 'granted') {
            window.addEventListener('deviceorientation', (e) => {
            document.getElementById('autorisation').style.display = 'none';
            //normalizing beta and gamma values and assigning it to global variables
            beta=(Math.round(e.beta));
            gamma=(Math.round(e.gamma));
            //Here I send those values to another function and I can use it
            increasePression();
            }
          )} else {
          alert("Sorry you need to authorize the game to use it.")
      }
  })
      .catch(e => {
        console.error(e)
  })
}

//Here I try to display the beta variable in HTML and it fails
//because I did not send params from above hte function above and it seems my var is not global
function test (){
  document.getElementById("stuff").innerHTML = beta;
}