Are you implying that Serena's crush on Ash was somehow a driving force for her development?
Because that is completely and utterly wrong.
Literally, the only meaningful thing Serena's crush did was give her an excuse to leave home and then join Ash. That's about it.
Quite literally, Serena just followed Ash around for about 60 episodes until the writers realized that the romance thing does not quite work because Serena was getting nothing out of it, and because Ash is fundamentally a character who does not care for romance or any romantic things. The entire "subplot" (and I hesitate to even call it that) ultimately led to zero substantial growth on Serena's side, and she did not actually start to grow as a person until she realized that everyone but her had some kind of goal or aspiration during the summer camp arc. All of her growth came from her Performer goals and aspirations, none of it came from her silly crush on Ash. So this idea that Serena's feelings somehow caused her to grow as a character is a legitimate delusion. The whole concept is hollow and it remained hollow until the very end, and it surely did zero favors to Serena's character.
Well, I will give you one thing. Her crush did make her very popular among Ash stans who love to see their boy being idolized by a cute girl. It's what a chad like him deserves.