My understanding (from watching a lot of YouTube videos - so take it with a grain of salt) is to not apply any coating because a good ceramic coating will reject it since nothing is supposed to stick to it - so for the most part it will be money wasted. If it does appear to stick, it will degrade quickly. Best advice I saw was to maintain the ceramic with regular gentle washes and in a couple of year repeat the ceramic application. Perhaps not the answer that you were looking for
Here is one video: