When casting to a web page on your PC, the audio is muted by default. At the bottom right corner of the cast video window in your browser, there is a "mute/volume" button (bell icon with a slash through it) next to the "fullscreen" button. Click it.
Yes I am well aware of that button. Clicking that button does nothing.
Try the basic casting to the default Meta webpage on another device or a friend's PC. You need to determine if the problem is an issue on your PC or whether it is a fault in the headset itself.
