Serena's entire character arc is realizing her crush was one-sided and that she had let a childhood memory define her life and prevent her from finding any kind of dream or goal in her life. Ash never reciprocates her feelings even once throughout the entire series, and her kiss at the end of XYZ was literally her saying "goodbye" to her past so she could move on and embrace her future.
I like Serena as a character and think she's the best and most developed female companion Ash has had, but come on now. The shippers are delusional. Everything about them tries to invalidate Serena's entire character arc.
