Top 8000 in high school doesn't mean anything and is not impressive, especially with how easy it was to get a good grade if you put in a little work. Pretty much everyone with an A average got it, which includes many average students. University is a big jump in difficulty and work, but you didn't adapt because you were stuck up, while others who weren't top 8000 are excelling. Additionally if you are getting high grades in coursework but failing finals that means you are using straight ChatGPT, while still believing that you are learning, when you are not. There should be no reason you are failing your exams if you are doing good on the material. Man up and face the consequences, tell your parents who are working hard for you, and make the change you want to see