Everyone has a different criteria for "chemistry" and this is mine: imo, even when characters do not want to be kissed in a "i love you but I can't do this" sort of way, it's doesn't give the dead fish vibe that the scene here gave me. In fact, it's actually more passionate than reciprocating the kiss
So even if it was a character choice for Sailom, the acting and chemistry is still horribly wrong in this particular scene
I think this will be a good fit for them. Earth as Maki, serious and eventually increasingly frustrated with Mix as Haruta (or atleast that's how I think how the casting will turn out. It might be cuter the other way round though, and funnier😂)
So even if it was a character choice for Sailom, the acting and chemistry is still horribly wrong in this particular scene