**Slight Spoilers**
Not sure, I'd call it a "romance" given certain things. If I had to summarize this movie, I think I'd say it's about "people changing". That conversation in the restaurant is probably the highlight of the film.
Was an interesting, but in a way sad movie.
True, it's an over-simplification to call it a "romance movie" alone. To me, it is, like you said, a movie about people changing (and, arguably, about how sometimes moving into a different socio-economic-political environment can help foster a greater expression of one’s potential and true nature), but central to the story, and what the movie spends quite a bit of runtime (and a leitmotif in "In-Yun") exploring, is how that affects the opening and closing of romantic possibilities/trajectories, so I think it is, at least in part, a romance movie, even though it's far from being a stereotypical Hollywood one (the ending was refreshingly non-Hollywood-like). Like you, I also found it to be a sad movie (hit pretty close to home tbh) and, yes, the restaurant scene was a standout.
But back to the topic, the new Fincher movie, “The Killer”, is an enjoyable watch, though a little cliche.