Traditionally a lot of analogue cameras were 4:3 for Fatshark or box goggles etc, especially race-specific cameras. Many 'newer' goggles ie Orqa, HDO2 etc allow the user to scale this 4:3 video to the full aspect ratio of the goggle display (in both cases above 16:9) or essentially stretched-resolution to utilise the full FOV.
Currently HDZero goggles do not support nor have the option to switch ; the goggle will auto-dectect the input aspect ratio from the camera / source. There was some discussion about the ability to scale analogue inputs correctly here - #145
It would be great to have this feature to utilise the high performance of the NANO90 4:3 camera stretched to the full display ratio, with the user simply being able to switch the displayed aspect ratio within the goggle menu. I personally have always enjoyed using this stretched camera layout on my analogue quads, and it seems like the display scaling option is not blocked by hardware as per the feature request linked above.