I'm looking for a school drama that focuses on the pressure, corruption and issues of rich teenagers, not a rich guy/poor girl or viceversa.

(for example the main leads being forced to date to unite their families' wealth or stuff like that)

I'd love it if the leads hated each other at first/the male lead was an asshole at first

Class of Lies is a great example.  The main leads (students) at the school are from very wealthy families and form a clique that through their parents or themselves run the school.  The main character is a lawyer who becomes a teacher at that school after he is stripped of his license to practice law because he did not kowtow to his firm's wealthy client to falsely imprison an innocent student to pay for one of their crimes. These wealthy sociopaths think they are totally above everything and everyone and think they are immune from all consequences for their actions until they tangle with our lead character.  The main lead student is a fascinating character study of his motivations and actions.  

Extra-ordinary You has a FL/ML engagement for the sake of their families.  The ML is only engaged because his father is forcing him to for business reasons.  He is a jerk but you start to see him rebel against his even more jerk of a father and I am hoping for a redemption for his character.  There is a lot more to this drama than that relationship.   (the characters are all part of a web comic story) 

 K Arlene:

Extra-ordinary You has a FL/ML engagement for the sake of their families.  The ML is only engaged because his father is forcing him to for business reasons.  He is a jerk but you start to see him rebel against his even more jerk of a father and I am hoping for a redemption for his character.  There is a lot more to this drama than that relationship.   (the characters are all part of a web comic story) 

yeah actually i was watching it when it came to my mind that i'd like to see a drama with a similar couple, except that i'd like it to be the main male lead and not the second lead. do you know any similar dramas?

I can only think of The Great Seducer, you got the whole messed up families corruption... but I realise that there is an annoying poor girl trope ahhhh...