I had exactly the same issue with my 2016. Anything above about 55MPh and there was shake that got progressively worse. Balance, rebalanced, RF balanced, had the suspension checked, then finally was referred to a "problem solver". He put the first tire on the balancing machine and called me in...the tire was balanced, but was out of round...you could see it as it was spinning. Bit the bullet and bought a set of Michelin's, smooth as silk now to 100MPH.
If you are under warranty, make them fix it.