I seriously appreciate this! I do completely ship Wesper, but I really don't ship Kaz and Inej. Seeing as how that's... yknow... the biggest SoC ship, sometimes it feels like I'm "incorrect".
You know you don't have to ship it just because is canon , right?
I mean,everyone has diferent ways of reading a text so if you think Jesper doesn't love Wylan then you can just not ship them. Is not a crime, just ship Jesper with Kaz or an oc with the same personality.
If you are convinced Jesper only got with Wylan because he couldn't be with Kaz or only sees Wylan as a reemplacement, then it´s okay, i just don't see why would you want them together if you see Jesper spending his life with someone who he will never love, and Wylan with someone that will never love him back, which sounds like a miserable relationship.
While is not canon that Jesper only likes Wylan because he is just like Kaz, if you read it that way there is nothing wrong, it just means the text didn't convinced you of their relationship)