Now you are just assuming she entered the Showcases looking for Ash's approval, this is not canon at all. The only person who can say why she likes those Showcase's activities is Serena herself and she never states why she likes filming pokevision videos, grooming, cooking and performing.
But if we are talking about headcanons, then I doubt she does all of those things just for Ash's approval. If all she wanted was Ash's approval, then she would be a trainer, because we all know how much Ash likes battles (just look at his face when Serena is battling Elle).
Yes she cooked for him once, just like Clemont, Brock, Tracey and Cilan did. That's a pretty common thing for Ash's companion, it doesn't actually means anything.
Being shy near Ash or using the ribbon that she received as a gift has nothing to do with Serena's goal, it has something to do with Serena's crush. Let's not mix those things up, after all a girl can have a goal AND a crush.
Admittedly motives behind entering Tripokalon(pokemon performance in Dendemille Town)may had been assumption.
But other situations didn't seemed that way. Ash was main reason and inspiration behind Serena going on voyage in first place. Sure some may try to pin it on Serena being fed up with life of Ryhorn racer trying to escape from that, but it was image of Ash she saw on TV and her feelings which ignited her in traveling wanting to see him again.
Baking macarons first time on screen was initially made for Ash as sign of Serena afection and admiration even stating they are gift for him.
Making pokevision video was likely influenced by her jealousy toward way Ash reacted to Elle giving positive review. Giving out impression how she tried herself in shooting mainly because of being driven by desire to get noticed by Ash. I believe my line of thinking is somewhat justified by finding Ash commendation of doing good job in video recording highly important starting to blush at end of episode.
Whenever Ash complimented her outfit or new strategy she came up with fior pokemon performnance being embarassed, shy and reclusive. With Ash opinion and approval evidently leaving big effect on her finding it more importnt than other people opoinions.
Signs such as using his gift as part of hr new outfit, growing with eacxh day more in her eyes considering him amazing never really opposing his advice or viewsonly add more and more to my belief.
How while i have no doubts that while main reason why Serena became pokemon performer is likely due to viewing this activity as something which truly makes her happy. Gives her way to express her talents and affinities in most optimal manner going with themes she has deep love for. Such as fashion, pretty dresses, baking, trimming, designing outfits etc.
I cannot shake of impression how small part of reason behind being performer also lies in trying that way through success to have Ash notice her and receive recognition.
With most episodes focusing on her mandatory containing clear signs of her crush, other characters teasing her about it thus making large part of her character consumed by romantic feelings.
Which isn't necessarily bad thing if its done in reasonable doses with there being drawed line between such thing serving as additional vector in enriching on character dynamic weaved with more humor and suspense. With writers doing farly good job regarding Misty or May romance subplots coming of as more independent.
Or making character your writing for too much defined by it to the point of overshadowing all of its other traits finding there exists room for improvenent in handling both crush, dreams and Serena story better than its case right now,
what
She was humiliated in front of a crowd in her first performance. She cried like a little baby. She screamed with her pokemons because she wasn't able to keep calm while training for the free perfomance. She had a lot of trouble trying to convince her mother that she was serious about the whole perfomance thing and that she wasn't a defeatist person anymore. She was completely lost in life trying to find her goal.
If you are going to complain about someone's plot being too lighthearted, then complain about Bonnie or Clemont.
I was talking about whole concept of pokemon performance, not Serena character herself necessarily.
Few far and in between scenes of small drama don't change fact of everything from character dynamic, rivalries, journey and plots being sappy, cheerful and too much hapy go lucky for my taste.
To the point that there never exists any misunderstanding, clash and very little or none darcasm, teasing between companions. Always being peaceful and positive making friendship unrealistic for me.
Rivals themselves not representing much of challenge or tension with likes of Scottie,Shauna, Tierno, even Miette based on last episode being friendly and considerate. Not delivering much of test or motivation for Ash and co to improve or build up on clash due to their abilities and competence never being questioined.
Villains are currently nonexistant and entire tone of this series is in shortage of any drama, clash or something to shake things up and prevent monotony.
This might change, but for most part thats current vibe im getting from this saga so far.