Thank you very much Tony for the additional information. I really appreciate your help in understanding what the issue might be so I can make an informed guess about what to try. That's a great idea to try to figure out what's going on over a phone call. We could start with my neighbor's TV on and then see what happens when I turn the TV on with my streamer on it. And then try moving the streamer to the computer (where I Zoom quite often) and see if that has any different effect.
Hm – the idea I might have to give up my streamer even for a short period while it's being checked out by the manufacturer raises some anxiety. That device has improved my life immensely by giving me a clear connection on Zoom and allowing me to give up the headphones. But you're right that Phonak should be informed if it's causing problems. And my neighbor deserves to be able to use her devices without interference.
Thanks again. Usually my experience with technology problems is pretty lonely and frustrating. It's great to have the support!