>>56339566Dawn competed in more contests plus actually had to work towards her goal.
May competed in less plus stole strategies and even her pokemon choices from better trainers like Ash, Tucker and the Beautifly trainer in Rustboro. This is something late AG even points out. May managed to fumble her way to Grand Festivals with Ash's supervision and being a rip off. This bit May in the ass in Kanto hence why she decide to break away from Ash to gain some originality in her training.
Dawn meanwhile had to grind and come up with her own strategies. Her Togekiss is really the only Pokemon she didn't have to put in the work to make a prime contest pokemon.
Basically, May had more luck than Dawn but Dawn has more drive.