wpgraft never reads Divi’s data. There is no exporter, no importer and no shortcode translator anywhere in this, by design, because those are the parts that break. wpgraft reads the page as your browser rendered it: the real elements and the real computed styles on each one, at every breakpoint you ask for. It then rebuilds that as Bricks’s own native elements, with the styles written into Bricks’s own fields. Nothing that arrives depends on Divi still existing.
Divi and Bricks store pages in formats with nothing in common: Divi 4 in shortcodes, Divi 5 in its own blocks, Bricks in a flat element array. No converter bridges that honestly. wpgraft does not try. It reads the page Divi rendered, at whichever version, and rebuilds it as Bricks elements with Bricks global classes.