Sounds like Jeep needs to replace the entire head unit in his JL.
I had a similar thing happen to my 2018 Subaru and it's top infotainment system, and a similar series of dealer attempts at resets and software updates and saying they tested it before it started hiccupping on the drive home from...
Speaking of chargers, Ford recently discontinued selling chargers for the Mach E after malfunctions, and is directing customers to 3rd party suppliers like Amazon.
You can see for yourself on the EPA website that they do not list Sahara separately. They list Rubicon, Unlimited, and 2DR, with the different motor types as applicable.
Their test vehicle must be a Sahara.
I just did an 800 mile trip in a 2.0 JLU Rubicon trip to Death Valley. Averaged 23 mpg. Mix of highway, back roads, and about 60 miles of off-roading.
The first half-day had me concerned because I only got 18.5 mpg. But that was the uphill part of the journey. It evened out after that.