On Roblox and Roblox Studio you are able to hide all Roblox UI with CTRL+SHIFT+G except for the microphone toggle above the player’s head. This makes it impossible for us to take screenshots for our content updates, promotions, etc.
Can you enable the New Experience Controls beta to hide the voice chat UI? Regarding the client you should be able to turn on the flag FFlagEnableInGameMenuChrome to true to hide the indicator.