There is no buzzing in my Quest 3s even at highest volume. It could be firmware but there is a possibility for hardware too. Sometimes a speaker unit can come loose inside and certain frequencies can cause it to vibrate. Is there a chance the speaker arm took a hit or was the headset dropped? As a music freak playing around with audio equipment in my younger days I found that even the slightest movement caused buzzing from a loose speaker. I found this issue even on the tiny speaker on an old Samsung phone I had. I jerry rigged a bit of putty around it and the buzz was gone. I'm not suggesting it is definitely the problem and I don't advise popping it open! 😁 But, you can definitely play Quest 3s at high volume without buzzing. So something isn't right. I'd contact support if I were you as it might get worse over time if it's a hardware problem.
