This is a great aggrevation to me also; I set my preferred zoom, then as soon as I slow down it automatically zooms in. Like you, I have searched to Owner's Manual to no avail, even though it does have 2 pages about the map.
I put this on the front. no drilling required. you could stow it in back until you drive thru a state requiring it.
https://www.extremeterrain.com/dv8-offroad-bronco-factory-front-bumper-license-plate-relocation-bracket-lpbr-01.html
Some states requite the front to pass isnspection. I just put...
I had similar problem with my 35" tires. The dealer went as far as they could with their road force balancing system. But problem persisted. Eventually they called Ford to get permission to replace 3 tires. A road force balance on the new tires was successful.
My dealer uses a Hunter Road Force...