It looks like you’re asking for a deep, analytical post about — specifically referencing the ePub format.
Before diving into a full analysis, let me clarify a few key points, since Only Hard Problems is part of a series that has specific context. Only Hard Problems is Book 3 in Estep’s Galactic Bonds series (a space opera with fantasy/romance elements). It follows Only Bad Options (Book 1) and Only Good Enemies (Book 2).