The D850 doesn’t have a built-in flash so the menu item is applicable only to external flash. I suspect the reason the D610 can’t be set to “ignore the background” is related to the capability of the onboard flash but not having a D610 I can’t confirm that. Camera built-in flash almost always has limitations beyond its guide number.I recommend clicking the "Flat View" option and rereading the whole thread. The Nikon D610 does not have such an option. The quoted manual section was explicitly stated to be from the D850 manual and to not apply to my camera.So, it is a Yes.So telling the camera that the background should be dark doesn't cut it either. Is there no setting "ignore the background"?
You can "ignore the background" by selecting "subject" only.