This is totally normal. The engine in the 4R is dead nuts reliable but is NOT anywhere near efficient and it changes a lot based on the way you drive.

Try this: set your middle user screen to the setting that actively shows your fuel economy based on the accelerator- if you turned off your green ECO light in the settings, turn that back on too, it will help give you another way to gauge. It isn't any fun to drive like this- you'll have to wait for bigger windows to merge / turn, be way easier on acceleration to reach top speed, and be more cognizant of "coasting" into a stop than accelerating until you have to brake... but you'll see that the easier you go on the skinny pedal can make a huge difference on your MPG.

I've played around with it and I can get reliably over 20mpg in the summer months, maybe 18.5 or so in the winter if I'm babying it- and this is with a lift and extra weight. My brother has a 5th Gen also and he doesn't care ("I drive it like it was meant to be driven" lol) and gets 15-16mpg.