As you can see in @linux-user screenshot above, the app shows roughly an area of 20x40km and still showing fuel stations. Depending on your screen resolution, you might be able to even show a bigger area. On my device I can show roughly a 30x60km rectangle and still see the fuel stations. You will have to select the fuel station map layer.
Adding an option to show POIs along the route (like the fuel station) have been discussed for example here: Extended search function for Food and Fuel
That’s probably what you are asking?