I think that I will miss one feature from PagePlus. The possibility to have non-printing elements on e.g. master pages that can be toggled on or off when printing or generating pdf-files. It does not have to be very advanced, but when I work with my editor, I add line numbers to the master pages to make it easier to name specific lines when he finds errors. When the job is OK I toggle off those line numbers. It is set as an option in the pdf generating profiles for "proof" and "print ready".
I can do that by setting a toggle on a layer on the master pages in Affinity. It works but it is not elegant.