Need to rent GPS along with Car rental ?

I suggest to use Sygic or an app which has an offline map - much better quality, also in forecasting travel times and prviding correct route. Google maps has some failures also in the locations and photos of sights - it is just bad quality of uneditored user-generated content.

Edit: Want to add the info that I did two North Cape car journeys with that system. In my experience new connections, tunnels, bridges etc. are built quickly in Norway.

We had an excellent experience with Google maps in Sicily including on many back roads. I had an Otalian SIM card for data in my phone.

I suggest to use Sygic ...

Let me check this out. Did not know about this earlier, but looks interesting given that it does not rely on internet.

We had an excellent experience with Google maps in Sicily ..

In general, I trust Google maps, just that little scared if there is no net coverage in some of the remoter places ...

Please let me add two examples for bad data quality of Google Maps (GooM).

Search for Olden Old Church in GooM and you will find this place. But this is not the right church; this is the right Olden old church: https://goo.gl/maps/BSwYDU9yBMcE8Xsc9

The Tvindefossen in GooM is located in the river but the correct location is where you find Trollafossen which is the name of the waterfall in official maps of Norway.

Actual traffic situation you get much better on official public traffic information system from Vegvesen.