so I just finished reading Risouteki Boyfriend and it was truly great. I was craving for more manga like this and decided to post this now. I am seeking for a male lead who is calm/stoic and smart. I prefer if the male lead is the same age or not that old.

“Hey, Mom. Why did you give birth to me?” – Ray

Try Machida-kun no Sekai
It's basically an improved version of the manga you mentioned in every regard. The male lead isn't smart with studies but rather emotionally as long as it's about other people, he's rather oblivious about everything concerning himself.

in need of romance?
uncommon, sad, sweet