From a personal view & through my own experience, I wouldn't trust a dealership to apply a ceramic coating.
For one, the car needs to be properly detailed & all swirls taken out, otherwise they will simply be applying the coating over bad paint, locking them in.
It took me a day of cleaning & a good work over with the DA to prep my own car prior to application. A second day using the Q2 prep & then applying the coating, & another half day going round it with a heater to cure it fully.
If the beading stops on the OP's car within a few washes, then I suspect it has only had a coat of wax, or at best a coating of wetcoat or the likes.
A properly applied ceramic coating will last years if applied & looked after properly.
For example, mine still beads well after three years as it has been maintained every six months with wetcoat to top up.