I use Sony WH-1000XM4 bluetooth headphones on my Windows 10 21H1 desktop. Windows separates bluetooth devices in the sound settings so that Default Device is audio only designated with Headphones and a separate playback device called Headset as the Default Communication Devices that has to be default when the bluetooth microphone is being used. For some reason, the Halo Infinite beta is starting with the microphone open and no sound is playing through my headphones. Unfortunately when the microphone is being accessed by Windows on bluetooth devices, Windows will only send sound to the Default Communication Device while Halo Infinite is sending audio to the Default Device. Many users on Windows will not know this nuance and think something is broken. My suggestion is that Halo Infinite should not be trying to access the microphone by default when the game is opened.
I tested a few scenarios where I removed microphone permissions to the Xbox app, Xbox Game Bar, and even all desktop apps but the issue continued. Changing the microphone in the Halo Infinite settings and even in the Sound settings of the Windows 10 settings didn’t fix it. It wasn’t until I changed the Default Device AND Default Communication Device in the Windows Sound Control Panel for the the Playback device to Headphones and the Recording tab to anything other than the bluetooth headphones that I could then get sound from Halo Infinite.
Any bugs for the game you should send to Halo Insider Support as per your Flighting information packets that you would have received.
Posting them on the forums isn’t going to them fixed or investigated.