The on/off road 18's is another lie Jeep tells. They are Michelin all seasons, designed for good highway performance according to the manufacturer. That one you can't blame on the dealer.
The factory installed cameras got jerky for many after one of the uConnect updates. Not sure it is anything the dealer can do about it. You might want to call Jeep and report the problem.
There is a TSB for vibration with 18" and 20" wheels, but I don't see one for 17's. But, it still might lead you and your dealer in the right direction.
As for bogging down in soft sand, are you airing down the tires to 16 - 20 pounds?