clearly an ongoing issue for many many people
You might think so because you are in that group. Yet it doesn’t affect all Fire TV users. So what is different between those groups? (Rhetorical question.)
I have tried multiple times to follow all previous advice
We have no idea what advice you have read or heard, unless you specify that.
Have you tried restarting the Fire TV device?
Have you checked for Fire OS updates? Apply if available.
What is your audio system? If you use your TV’s built-in speakers, then please set your device to Stereo output, else surround sound audio channels might be routed to non-existent surround speakers.
If the issue persist after all that, then please contact the Apple Support staff for their insights.
Please look up the exact model Fire TV stick, as that can be helpful in troubleshooting (capabilities, limitations).