I think you put it well. At the scales our brains are familiar with we experience "emptiness" as a kind of space which can have things placed in it. A chair is

I think you put it well. At the scales our brains are familiar with we experience "emptiness" as a kind of space which can have things placed in it. A chair is empty if you can sit on it, a box is empty if you can put something in it. The sub-atomic "empty" space is filled with fields of various kinds. You could not place something where those fields are. The spaces are not empty. When you fill a box with things, you are filling it with sub-atomic fields.