Nothing really helps when everyone is voluntarily buying always on surveillance tubes, headphones and glasses with Alexa/Google assistant that's always listening

I could imagine a mini-microphone playing continuous noise of the appropriate 'color' to mask everything.

Then turn off the speaker when you want to use the mic.

Or do what Snowden does and de-solder the microphone and rely on manually plugging in a mic in the headphone jack.

I considered doing that and using an external microphone, but I don't trust my skills to get everything back together in one piece. Even getting access to the board to do it seems to require the use of destructive force. I'd probably be perfectly fine with a phone that didn't include a mic and required an external one though. While I do use it to place and answer calls sometimes, it's almost exclusively used for texting, and I haven't run into an occasion where loss of audio while recording video would matter.