wpgraft reads the page as your browser rendered it, the real elements and the real computed styles, at every breakpoint you ask for, and rebuilds it as Beaver Builder’s own native elements with the styles in Beaver Builder’s own fields. It does not care that a language model wrote the HTML, and it does not care what framework the page was built with: by the time wpgraft looks, all of that has already become computed styles.
The awkward part of building a page with Lovable was never the generating. It is that what comes out is HTML, and what you need is something you can edit in Beaver Builder next month without opening a code editor. This closes that gap: the generated page is rebuilt as real Beaver Builder elements, so the next change is a click in a panel rather than a prompt and a re-paste.