Yes, XY007 is basically the only one of the Serena dedicated episodes where she actually address her personal problems. The other episodes being the Pokevision episode with Aria's debut and the Pokepuff episode with Miette's debut, but in any of those situations Showcases (Serena's actual goal) were mentioned. This was only added until the Summer Camp arc when Serena starts to ask to herself what she wants to do. But before of this? Almost Zero episodes addressing her actual problems, which is why I don't blame people for saying that they feel that the writers didn't have a clear plan for her in XY first year.She has a whole episode dedicated to understanding that perhaps she thought wrong about Rhyhorn Racing.
Also this argument about small "moments" showing apparently "progress" can be say for almost all the main characters in Pokémon from OS to JN and not exclusively for Serena, but without actual major plot addressing the character problems, it is not a proper arc.
Saying that Serena's character arc started in XY001 but not addressing her own problems during the first 40 episodes except for 1 dedicated episodes is like saying that Sophocles arc started in SM005 but never addressing his own problems until mid SM.
She had a clear plan in mind for XY years 2-3, but first year was awful.