Used 2022 Genesis G80 Advanced 2.5T 3.5T Sport Prestige

This car is a vehicle of my dreams. I have a 3.4L Twin Turbo with AWD and the Prestige package (I highly recommend the Prestige package). The owners manual leaves a lot to be desired. It is hard to find explanations of the numerous features. For example, I have two buttons, cryptically labeled, on the overhead panel where the dome light and sunroof controls reside. I cannot find the difference between the two buttons in the owners manual. Both light the dome light but I cannot figure out why there are two buttons for the light. That is just an example - the manual must have been translated from Korean, and poorly at that. Ride is smooth as silk, with windows closed a boom box next to my car is silent, acceleration is remarkable for a car as heavy as this. Gas mileage is terrible though. Around town, I get 16 mpg with a light foot. On the road, I get around 19 mpg. Wondering if there is something wrong with my fuel delivery system. Have not asked Genesis for valet pickup and drop-off of my car for service but based on comments in the G80 blog, dealers are reluctant to deliver on the promised service, not to mention they say loaner cars are not available.