Simonb I've been experimenting with various ideas, but not happy with any of them!
I wouldn't know how to approach it in a jazz way either! In non-classical terms, there are a lot of hooks in the song, and their intertwining is what makes it catchy. You could just do it as a chord progression and mostly ignoring the hooks for the improv part, like Hiromi did in some video linked above. The kdrama approach that Sophia and I used was to take one hook and just focus on that, discarding the set chord progression.