Can't speak for Android or Samsung, but the Apple people may not be making (or may not understand) the distinction between the GPS receiver hardware, and the display software. The GPS receiver supplies position data to whatever display software wants it, for whatever reason. Apple reps may be referring to their own in-house Apple Maps app, which does require cell or WiFi connection in order to display a GPS position. But there are hundreds of other programs (apps) for displaying GPS positions in lots of different ways available in the Apple Store for installation on iPads and iPhones. Some, like iFly GPS, WingX Pro, ForeFlight, and CoPilot for car navigation do not, repeat, do not, require cell or WiFi contact to function in your plane or car. Same for Android, but I've never used them. The Apple people may be directed to address Apple products only and not acknowledge the existence of the rest, even though they sell them. Hard to believe, but possible. Or you may be talking to somebody half a world away who's just reading a script and has no idea what it means.
If you are set on an Android unit, Cdrmuetzel's Avare sounds like a great place to start. It's free, so how could you lose? Download, install and use it for a while. Once you learn what's going on with it, then you may choose to consider something more complex, that you would have to pay for, that would give you even more capability including your "turn by turn" directions.