Ceramic coatings are not magic. They make washing easier and they last a couple of years if you look after them. Anyone telling you it is bulletproof is selling you something.
Corrected a black E39 last weekend and it took nine hours across two days. Black looks incredible for about four days and then it is a part time job you did not apply for.
Genuine advice and it is free. Stop washing with a sponge. Two buckets, a grit guard and a decent mitt will do more for your paint than any wax you can buy.