Welcome to the boards, you are more likely to get replies by starting your own thread instead of piggybacking on another one. Also most of the replies to questions in this section are answered by fellow collectors (like myself) and/or dealers not by employees of NGC. The way to tell the difference is that employees will have a light blue background surrounding their name everyone else is dark gray.
As to your question die cracks and die chips are interesting but do not; in most cases; add any value so there is no reason for folks to pay (grading plus the extra fees for variety/error service) to send them in. Submitters of modern coins are mostly interested in ultra high grades, only an extreme die crack or large retained rim cud would be worth the money to send in. So while NGC graders may have seen many 2020 dimes, I doubt that any have been submitted for the reasons you ask about.