Ever since TomTom took me down a 13 percent downgrade in the Catskills, I have a healthy disrespect for GPS. I still have the TomTom, the DW uses it. When she says "TomTom wants you to turn" I just keep going. It's mostly so she can check the speed without being obvious.
I use Waze and and Copilot RV phone apps on my tablet for traffic and guidance. I check the route on Google maps and/or Google Earth before hand and keep a mental route in my head so when the app says to do something, I can use the TLAR method (That Looks About Right).
If the route involves terrain, I use the mountain guides. And as if all this isn't enough, the DW always has the paper atlas out.
There have been a few times when I just needed to pull over to make sense of what's going on. The most notable was when headed to Sylvan Lake CG in New York. The directions said to get off I-84 at exit 15 and then follow this road then that. None of the road signs made sense and the circle of our position error was increasing in radius. I pulled over and punched the address into the GPS. We were 75 miles from the cammpground. We took exit 15 in Connecticut, not NY.