I am pretty sure it was a manhwa 355v4l

Possibly twins/Brother one of them doctor or lawyer and other works as something else ?? I can't really but the sibling are the top. One is cold/not that caring/cruel and may not like the main character/uke and the other is a lot kinder Uke possible undercover or something, possibly trying seduce one of them i can't really but he may have met with the colder one in a building then when leaving may have ran into the other

Sorry it is not much and all over the place and sadly really is all i can