-- the universe won't wait for you
The thing is that Serena is not going to change just suddenly. I'm hoping to see her set aside the fangirlish crush as she realizes that Ash has changed and grown without her and is different from the fantasy version that exists in her mind. That separation should lead to her being more willing to call him out when he's being dumb or questioning his judgement. As she grows more comfortable with Clemont, I'm sure that sort of interaction will happen between them as well. She's not fully integrated into the group yet imo. She's fixated on an idealized memory of Ash (rather that who he is in person) and just starting to become a big sister to Bonnie. Sisterly interaction is almost if not always instigated by Bonnie, too. Serena has little to no standalone relationship with Clemont yet. She's an outsider to the little family that formed in episode 2. Once she becomes integrated and relationship types and roles become more defined, then we'll get more of an idea of how the ships would play out.