The South Korean-born video essayist turned filmmaker who goes by the mononym Kogonada emerged in 2017 as an assured new voice with the exquisite contemplation of physical and emotional architecture, Columbus. He confirmed that promise four years later with After Yang, a soulful reflection on identity and connectedness, not to mention a refreshingly open-minded view of the potential for A.I. to enrich rather than intrude on our lives. Kogonada continued sharpening his craft directing episodes of Pachinko and The Acolyte, before stumbling last year with A Big Bold Beautiful Journey, a high-concept romantic odyssey too precious and contrived to strike authentic chords. As a first step into larger-scale, star-driven (Colin Farrell and Margot Robbie) studio filmmaking, the movie’s critical and commercial failure must have stung. It’s understandable that Kogonada might crave a radical creative reset by going back to basics with an intimate, shoestring-budget film made on the fly without binding structures or complicated logistics. Such throat-clearing purification makes sense. But the resulting project, Zi, sad to say, is too wispy to be compelling as …