Nearly every week a Windows 10 user posts the same complaint: a cheap Bluetooth headset pairs instantly, the system shows it as “connected,” the microphone works for calls — but there’s no music, no system sound, or audio quality collapses to a hollow, mono tunnel. This is not a mysterious hardware failure in most cases; it’s the predictable interaction of Bluetooth audio profiles, Windows’ legacy stack, and the cost-cutting choices inside many discount headsets. Readers buying “hot...