I think Orville captures the Gene Roddenberry character style a little better than Lower Decks, in homage to TNG and others of that era, meanwhile Lower Decks is both more of a "true" Trek while also being a meta commentary that's separate but adjacent to the main storyline. So Orville is kind of ahead of Lower Decks in terms of its significance to its universe, while Lower Decks is a bit more authentic.