Nikon d720 was out of focus when the shutter was pressed lightly, leaving only one focus, which was a bit virtual.

That's because you adjusted the focus. Can you adjust it to one focus and one focus? If you are in focus, you are not out of focus. You can set the focus. In fact, portraits usually focus on one point. The focus is on the face, or rather on the eyes. If you focus on other places and the aperture is large, the out-of-focus place must be empty.