Bhai i said cleaner wax will do no good unless u treat the paint to remove contaminants and oxidation!! The cleaner wax contains micro abrasives which will merely treat high contamination on ur paint! U need clay bar!!
But first ur roof with shampoo, the remaining wax will become stubborn n it can damage ur paint. remove it asap!!!
I recommended full paint because i was discouraging u from going for paint treatment as on Mustafeez bhai's B13.
The results u r looking for cannot be attained without full paint!! Preserve what u have, treating it will only result in a 'bald' margalla!!
wash ur car thoroughly, dry it properly n then drop by my place!! I'll test all the products i hav on ur car.