When I start up my Phantom 4P+ it does its satellite thing and eventually says “Home point … Check it on the map” but when I check it, there is no map. The home point is clearly shown on a blank screen.
You must be connected to the internet to get the maps. You can cache them locally before you go fly beforehand if you do not have access to them while in the field.
Since on P4P+ DJI GO Maps does not display any maps in real time, does this mean my device is not connected to the internet?
And, if it is not connected, how do I connect it?
It means your remote controller is not connected to the Internet and the maps have not been cached (which allows them to be used when not connected to the Internet).
Swipe your finger down from the very top of the screen and connect your remote controller to a nearby Wi-Fi network.