Regarding the 'always listening' concerns, on Android 6.0 and above it is possible to grant granular permissions for resources such as microphone or location to applications. Even on applications that use an older SDK where granular permissions are not a thing, you can still disable those permissions after installing the application by tweaking the System Settings.
By looking at my current permission settings, only the Camera and the Phone app have permission to use my microphone. I closed my Facebook account a while ago but I use WhatsApp, owned by Facebook. Given that I don't send voice notes or make in-app calls, there is no need for it having access to my microphone. Same with location — no need.