Is there some trick to block the Netflix "BangBang" sound?
This is a manual (non automatic) workaround.
I installed this app:
https://play.google.com/store/apps/details?id=com.alwaysvolumebutton
It is highly configurable. I can move the buttons, rotate them, and make them transparent. And the volume percent shows on the button.
So with 1 click, i can quickly mute sounds and not show the bright annoying system volume control. To mute is a initially disabled option.
So, b4 clicking on play, i hit the mute button, and again after the bangbang, and that is very simple to use.
It may be buggy to configure, but as soon you manage to, it works fine.