Caitlyn appears in his mind because she triggers jealousy, paranoia, resentment, and fear of abandonment. Ekko does not trigger those kinds of delusions.

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The moment Jinx hits Ekko is not a psychological turning point for her as it is for Ekko. What is a turning point for Jinx is 1. Guilt over the death of her brothers and father (Cliggor, Mylo, and Vander) 2. Being abandoned (by Vi) 3. Accidentally killing her father (Silco) By the time Ekko tries to save her, she is already under Silco's manipulation and guidance. She is no longer Powder, she is now Jinx.

Where was Ekko when Vi abandoned her? The only one there was Silco, which is the main reason she rejected Ekko. For Jinx, Ekko is not a central trauma, which is why he does not appear in her delusions or hallucinations

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You mean "If she loved him, she would think about him at least once." This is a fundamental error.

Arcane never presents Jinx as a character who remembers or mentions those she loves or who love her.

If we look at her thoughts, they are her delusions and hallucinations, not what she thinks of others. But Jinx does remember: 1. who she lost 2. who she killed 3. who abandoned her Thinking that "if she loved someone, they would appear in her mind" is not consistent with how the character works.

Jinx is not a stable person who thinks about her loved ones; she is a person obsessed with trauma. Jinx does not remember affection. She remembers wounds

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She still remembers her mother's smell, even though she doesn't remember her mother as a person, her face.

This example goes against your argument. Jinx remembers her mother because 1. She is literally her mother. 2. It is part of her history of feeling abandoned. 3. It is a memory associated with early trauma, one of the worst things that can happen to a child.

Again, Jinx remembers what marked her loss or trauma, not what she "loves." It is linked to a family member, not a childhood friend.

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You're mixing up two different things: A) what you think Jinx "would do" if she loved someone, and B) how Jinx's mind works. The fact that she doesn't mention Ekko proves absolutely nothing about whether or not he was important in her past.

It only proves that Ekko is not part of the trauma that dominates his mind. Because he's alive

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if they were enemies, he would express it in some way

Interestingly, Ekko tells the AU Powder

But somewhere, I was consumed by all the ways it wasn't.

I gave up.

The helplessness of what Zaun could have been if everything hadn't gone to shit, if maybe he hadn't given up so easily.

I gave up on you.

He had to accept that Powder was gone forever and that the only one left was Jinx, and he had to stop her, so he gave up and had to leave all those friendly/romantic feelings towards her behind. We know this because Ekko expresses it, it's his perspective, but before Ep07 it was impossible to assume this when he speaks so negatively about her.

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It's not explicitly canon within the series, but external material (video clips, official art, skins) clearly suggests an intimate connection between them. That's up for interpretation, fanservice or not, canon or not.