On MacOS 10.15 Preview, I drew an "annotated" black box over a paragraph that was recognized as text. I exported it in two ways, 1) "Export as PDF" and 2) Print -> Save as PDF. Both results did not include the underlying text under the box.
That's not to say it's definitely not there, but it's at least something.
That's not to say it's definitely not there, but it's at least something.