As you will be well aware, neither of those "import" files are vaguely intelligent file formats. It's nearly as much use as defaulting to the import of a *.txt file into a modern word processor - marginally better than copy-typing, but all the formatting and typography has been lost.
As Serif now classify PagePlus as "legacy" and are apparently no-longer updating even X9, the product and its *.ppp format can have very little commercial value to them.
As you are clearly simply abandoning your loyal old users, how about releasing the *.ppp file format documentation to the Serif community so that a community effort can have a stab at developing an "intelligent" xml parsing routine for an open source alternative like Scribus?
Caspar got a reaction from birchlight in importing PagePlus files into Affinity