The only solution is your phone
Use Waze or Google Maps. Never has a car company shown so utterly and completely that they have not the slightest idea how to fix a problem. I have had 50 failures in 10 months, including one drive when it showed I was driving through the middle of the Seabrook Nuclear plant in New Hampshire (I was on I95 at the time).
Car has been to the dealer a half dozen times without any beneficial result.
Yesterday, driving down the road with the nav system working, the radio and nav system shut down, rebooted, and had not the slightest idea where I was.
They will never fix this problem.