A recent long thread with all the same answers / opinions.
BTW, a wax and a polish are not the same, explained in linked threads in the above. A wax (or more appropriate for an RV, a sealant) protect the paint, a polish “corrects” the paint and is generally applied by machine, and needs to be followed with a wax / sealant. While there are cleaner waxes / sealants that contain “some” polish, as with most “all in one” products, it’s generally a compromise.
Lots of reading if you are interested, but in short, it’s all about your own expectations, and how much work / time / effort / expense you want to put into. Getting into detailing with an RV is an uphill learning curve if you haven’t done much with your cars to give you a starting point. Pick an appropriate product from the long list of suggestions and see how it goes from there, because there is always another one to try....
I will add that some of the spray finishes are getting better, including the Ceramic Infused products, but durability / how long they last on an RV in particular given being outside all the time and how often you want / need to apply them is a question / consideration.
Also, how you wash your coach is even more important, with plenty about that in the referenced threads as well.
Pricey is relative.... my post #84 in the attached link is a reference to what pricey can entail
, but I really wouldn’t consider those products appropriate for an RV anyway