Hibike! Euphonium, Yagate Kimi ni Naru Recommendations
While Hibike! Euphonium isn't centered around romance, I think both have some similar themes such as hiding one's feelings and dealing with the struggles of growing up. Also, the main characters' personalities and interactions remind me of each other (Oumae being similar to Koito and Asuka being similar to Touko). Both shows reveal multiple facets of the main characters' personalities and touch on believable doubts, thoughts, and dreams that people might have in high school.