When you do not want to share your live face in a zoom..
Create a recent shot of you facing the camera by going to zoom settings,
Change the name appearing on the screen to a name that will identitfy you properly to that audience.. otherwise you have a senseless thiing like the brand name of your phone going through. Quite frustrating for the moderator.. It is also better to take a profile picture in your current settings, and save it in your profile, so that even if you have to switch off your video, your proper face to the camera is seen.
This is particularly useful if you bandwidth is low or your internet connection is unstable.. in which case even when your bandwidth is low you can speak, as audio is carried or at least "buffered" in very low bandwidth.
It is wrong to assume that if too many people have their videos on in a zoom meeting, the bandwidth required for low bandwidth areas is affected. Zoom has worked out the algorithm that the receivers in good bandwidth areas can see your profile pix, while hearing your audio, albeit in buffered mode..
Finally asking if your are audible is a no no, and it distracted the flow. Just look for the green outline on the picture in the gallery mode.. Putting your zoom meeting in gallery mode when you are speaking is a good thing because you can then see how your audience is receiving your message.