@Brian-Eastham-0
I did use this adaptor when I had the Nav6.
Connect the nav direct to the iPhone and connect power to the adaptor.
1619376671674-1602606006776-schermafbeelding-2020-09-15-om-13.55.05.png
1619376688049-1602606031830-schermafbeelding-2020-09-15-om-13.55.09.png
As a result, the iPhone sees your NAV as extra storage.
Now you can place the route on the Navigator from the MyRout app from the Page Menu -> Save as -> choose file type -> Save to Files -> [Garmin/GPX]