One thing in general I'll bring up since it hasn't been mentioned is that there are certainly pros and cons of a ceramic coating and depending on how you maintain, use and store your vehicle should be considered.
With the cons for ceramic coating you have to consider they can be more susceptible to water spotting and if not checked, allow the minerals in the standing water to etch the paint (also the downside to a paint protection product that produces a beading heavy result vs. sheeting). So, if the vehicle is not garaged and you won't stay on top of it, going the sealant/wax route may be best as many of those products stand up better to water spotting. Like a sealant or wax, the coating must be maintained or you will not get the advertised longevity. Typically brands offer boosters or toppers that must be applied at least quarterly. Of course, the harder the vehicle is driven or if stored in the elements, the more effort to maintain the coating will be required to achieve the advertised longevity and the less likely you are to obtain that longevity. When considering install, as folks have mentioned prep is critical, so varying degrees of polishing will be required depending on the condition of the paint. Of course, that is generally true of any protection you apply.
One misconception, more so than a con, is that ceramics are going to prevent rock chips and heavy scratching, which is not the case. If 9H hardness is mentioned by the coating manufacturer, it's measured against a scale related to the hardness of a pencil lead (which is now graphite) not the 9H in the Mohs scale, which refers to hardness of minerals (think one step below diamond hardness).
Of course there are many pros to a ceramic coating. One big pro for me is if I'm going to need to do paint correction to apply a paint protection of any type, if I can do less of it (lasts longer) and have less steps (time) to apply and get what amounts to better protection for my use case, it's a win. Also, cleaning is much easier and from my observations, using a waterless wash product is more effective with a ceramic coat, so it could make winter washes in the garage doable.
I'll add, PPF needs to maintained as well. The top layer is a clear coat like your paint, so ceramic coatings can be applied to provide that protection to achieve the longevity and effectiveness of the product.