Agree, die crack, and a rather large one. These are often seen on silver, nickel, and copper coins but are much less common on gold pieces. It might add some appeal to the right buyer.
The coin has strong AU detail with remaining luster. I don't see any obvious hairlines from abrasive cleaning but it looks excessively shiny, particularly in the angled photos. It has likely been dipped in an attempt to brighten it up.