Does the starlink app need cell service to work? If not how does it get the map view?
Yes, you currently need to have either cell service or WiFi available to have Starlink display an accurate map view. I typically set up my cell phone as a hotspot to achieve a position for the map view, since I don't have cellular on my tablet.
It would be nice if there were an option to download maps at home for use later in the field for areas where you know cell coverage is an issue. But that is a lot further down on my own wish list than the fixes for several important control issues that are present in the ship.