The Chang'an Youth (2020)

Shen Yi Yi lives in the city and has excellent cooking skills. When she was young, she was friends with Shen Die Yi. Die Yi abruptly dies of a cough and her life remains a mystery. In order to repay her friendship with Die Yi, Yi Yi poses as Die Yi and heads to Chang’an Lu Xing to fulfill the marriage contract. As well, she wants to find out the truth behind Die Yi’s life. In order to delay the marriage, Yi Yi dresses up like a man and enters the Shangyi Guan alongside with Die Yi’s fiancé, Tang Jiu Hua. They also meet Yang Zi An who was ordered by the emperor to hide his identity and enter Shangyi Guan. Together, Shen Yi Yi, Yang Zi An, Tang Jiu Hua, second prince Li Xin Yuan and swordsman Du Gu Mu Xue solve many strange cases. They face the embassy of the East Kingdom, and form the “five sons of Shangyi Guan”, becoming famous in all of Chang’an. Together, the five must ride out the difficulties and bring peace to the kingdom.

- ML and FL are smart and study in imperial school
- ML and FL solve case
- Ml is a nobleman while FL is ordinary citizen
- ML is very straight laced/ stoic

The school aspect is similar and the general atmosphere of both dramas as well. Multiple leads in both dramas.

Same premise - it's a romcom about crossdressing female lead who enters Imperial College and pretends to be way less competent than she is to protect her identity and reach her goals.