Recording Zoom video without showing participant faces

As a host, in the bottom tool bar on the screen click the icon on the right to open, and then click 'Focus Mode'. This will prevent other's video from coming on the screen, and you can still hear and talk to them. 

Did you ever figure this out? That’s exactly what I’m trying to do too.  

If the intent is, like in my case teaching an online class, for the instructor to see the gallery while the class is going on, but not have the gallery show up in the published recording, nor any participant become the active speaker in class or recording, then it is like Woodturner1 wrote - in Settings, under Meetings > In Meeting (Advanced) > Focus Mode (set on). And most importantly, during class, when recording, set "Set Focus Mode" on. Note that the the instructor can see all participants in the gallery during the class, but it seems that the participants don't see the gallery during the class, which is not so terrible, because the important part for me is for no participants to be seen in the recording. When screen sharing you get the shared screen only. It's a good solution for this particular scenario.