To. Jenny (2018)

Both are drama special. Good when you want to spend time watching something short and memorable. The music in both movies are good!

I just want to recommend this because the lead in this web drama is one of the COCOA members (DIA) which is Kwon Eunchae

Try it it's good.

I can almost guarantee that if you like one you'll like the other. I don't want to spoil anything, but they both share common themes in perspective, romance, music, and life. I can't recommend .to Jenny enough, the only problem it has is being too short. Though do be aware the OST for .to Jenny will get stuck in your head for weeks or in my case months. It is spectacularly wholesome and will really pluck at your heart strings.

Both ML have stage fright. Character development. All songs (OST) including BGM(???) are GREAT!!! MUST WATCH if you like The Box ;)

Both short kdramas
Both revolve around the topic of music
Both follow leads who want to follow their dreams

Both are "feel good" mini dramas. In To. Jenny ML teaches FL how to play guitar, whereas in Understanding of dance ML teaches FL how to dance without being embarrassed.
Really cute dramas, both of them.