Best answer by Edward R
The update may have indeed indirectly caused the issue. It is possible that a failing component has been pushed over the edge by the necessary reboot that occurs after an update is completed. I think you are most likely correct and that the PLAYBAR itself has encountered an internal failure. Does the wireless headset still emit audio? Given how thorough you've been I assume it does. If so, this rules out any issues with the settings on the television. The final thing to try is a Factory Reset on the PLAYBAR itself. Please be aware that this will necessitate the setup of the device from scratch.
If the issue still occurs after you've set the device up again, it does mean that it will need to be replaced. For this, I would urge you to get in touch with us via telephone, this way a return can be initiated. The return process is rather painless, though it would be great if this could be avoided altogether. Please do let me know how this goes.
All the best.
A note to anyone reading along: Please do not perform a Factory Reset unless expressly advised by a Sonos representative.