wpgraft never reads Beaver Builder’s data. There is no exporter and no importer anywhere in this. It reads the page as your browser rendered it: the real elements and the real computed styles on each one, at every width you ask for. It then builds that as a Shopify section made of theme blocks, with every style in one of the blocks’ own settings. Nothing that arrives depends on Beaver Builder still being there.
This move crosses platforms: Beaver Builder is WordPress, Shopify is a hosted store. There is no plugin and no export on either side. The copy is made from the page Beaver Builder rendered and written into your Shopify theme from your own admin tab, and your Beaver Builder page stays where it is. What moves is the design; products, orders and checkout are set up in Shopify itself.