Anyone know how to do this on the Fios one voice remote?
The fios box can only control audio levels on its analog outputs. When you program the remote in the setup menu, you are programming it to control the volume on your TV, soundbar, or receiver. That's why you still need line-of-sight for the remote to control volume or mute the sound. So go into the menu on the box, look for fios voice remote and program it for your TV model.
In some cases, you may have to manually enter your specific TV and Audio equipment information. Follow these instructions to do so: