Sadly I don't think you should get your hopes up. Back in the late 2000s a fellow named Greg Olsen put together a giant book that looked at Lynch's entire filmography up to that point, and he got to directly interview Lynch a few times. He asked Lynch if he'd ever consider returning to Dune to do a director's cut, but Lynch simply replied that as he saw it there simply wasn't a better film to be salvaged from Dune. While Lynch could always change his mind, I feel like he closed the book on Dune a long time ago and considers it a project that didn't work out that he wasn't really suited for, but taught him a lot about Hollywood and created opportunities to make the sort of movies and shows he wanted to make afterwards.