Hello. I took delivery of my 2020 Cayenne S Coupe a couple of months ago. I had Modesta ceramic coating as well as Xpel protective film put on. The ceramic coating is amazing and I would highly recommend it. My car requires no real washing and no waxing. I simply rinse any dirt off the car and wipe down with a waterless spray and the shine is like a mirror. If your dealer has an experienced ceramic coating guy you should have nothing to worry about.
The debate goes on about ceramic coating. The brush on /spray on is not really ceramic coating, in that actual ceramic coating with require 1500 degrees Celsius. e.g., liquid glass
Ceramic coating is a very loosely applied term, not as bad as bonded leather, but close. I did the ceramic coating, Mothers. CMX. Granted the nano particles are hydrophobic, repels water. But is it a wax suspension, that will wear off. IMHO, twice an year good quality wax just a s good.
Also "Wax on Wax off." No need to go to the gym.