re: I believe the conspiracy theories now: iPhone or Alexa listening to convo

Do your phones have the jack to plug in external audio? If so get some cheapy headphones/ear phones with mic but cut the cord below the mic or even just past the plugin so no cord dangling. Phone switches into audio jack mode but then lacks the ability to send/receive audio.

There's probably already phone cases/covers with some sort of slide cover for the camera lenses too if you want to get completely paranoid about hijacking the camera to spy.