So I went and built a quick test
https://twitch.extensions.barrycarlyon.co.uk/temp/player_test.html
Everything works as expected.
You’ll first need to hit “unmute” and then setVolume works
So the only fix you’ll need is
function setupTwitchPlayer() {
var options = {
width: 1280,
height: 720,
channel: "BastiGHG"
// parent: ["embed.example.com", "othersite.example.com"]
};
player = new Twitch.Player("twitch-container", options);
player.addEventListener(Twitch.Embed.VIDEO_READY, function() {
player.setMuted(false);
player.setVolume(0.1);
});
}
https://twitch.extensions.barrycarlyon.co.uk/temp/player_test.html?test=1
And then deal with the interaction score/autoplay blocker that browser have