Update: Oct 2021
Just after the latest update. I had the HUD displayed on my external views.
The solution below is not a Toggle but simply a way to clear it or put it back on.
1) The General Options > Camera > Chase Camera > Instrument Heads-Up Display (HUD) - is no longer present!
2) Go to the ASSISTANCE OPTIONS - USER EXPERIENCE. Click the down arrow, see Instrument Heads-up Display -Chase Cam. Switch this to OFF
Hope this Helps