Y'know, the existence of a romcom genre savvy dude who views "real life" through the lens of a romcom and thinks of himself as a background character. Means that there's a non-zero chance of another romcom brainrotted freak enjoyer somewhere nearby whose goals could be in opposition of our guy here.
I think it would get way too convoluted and derail stuff but it would be really funny if some other guy who applies romcom values to "real life" but roots for the main-heroine instead, or someone who interprets our main dude as the hero instead, or a yaoi fujo who's super down for Kimura/Ei (or Ei/Kimura if she's wrong).
I don't think any of this is gonna happen but it's interesting to think about.