In that case you might want to try kepubs.
For reading epubs, the Kobo and Sony devices use Adobe RMSDK. This does the page number according to
https://wiki.mobileread.com/wiki/ADE#Page_numbers. That means that a screen of text is not a page. The good thing about this is that the number of pages does not change with font size or the other reader settings. It is also consistent across all Adobe RMSDK based readers. But, a lot of people don't like it.
Kepubs are Kobo's version of an epub. They are basically the same as an epub, but with some Kobo based tweaks. An important thing is that they use a different reader application. This does page numbering per screen. When the font or other settings are changed, the page numbers are recalculated. But, the page numbers are per chapter. Some people love this and some loath it. There is an unsupported config file setting that will change the page numbering to per book.
If you want to try kepubs, you need the KoboTouchExtended driver plugin. You can install this from within calibre. There is also a kepub output plugin to convert the books in the library of you prefer that. Threads discussing both are in the calibre plugins subforum.