Given Dohyun's flashback and his confession that he likes Irae because she is a kind and nice person, it actually reveals a bit about him. To me his confession is honest but also leans towards a more guarded and careful/safe mindset. Irae feels like a good and relatively safe option. Not that he's over confident and thinks she'll automatically like him, but more in the sense that they would likely fit well together and they get along pretty good. It's not passionate feelings, but that doesn't necessarily make them less valid. Sometimes a person values a sense of security and companionship over being impassioned, especially with Dohyun having experienced heartbreak already. It also works as a contrast to Kang's method which is an energetic "give it all" approach but also clumsier and more childish.
Neither approach is necessarily better/worse, but it touches again on the age gap theme in contrasting an 18 year old to a 26 year old in approaching romance with the same girl. Each has their own insecurities but for different reasons.