My son was starting to go down that path of not caring about grades. I sat him down and talked with him. What I basically said was:
You may apply to a college but it is the college that really chooses who they will admit. The college will want someone with a paper trail of doing good work in ALL subjects. That paper trail is called your GPA. Many colleges are getting away from SAT and ACT test scores as they are just one day tests and GPA is much more telling about how you perform.
College isn’t the end game. It is just a stepping stone to your career. You must also perform well (read good GPA) in college to get the job you desire. You will also have to take classes in college that may not always be to your liking, but that is life and you can not change the system.
Learn to play “the game” now or fight the system your whole life. Fighting the system is like banging your head against a wall. It feels good only when you stop.
So, you have choice. Get to work now or be shut out of the better career paths. It’s your choice.
He decided to not fight the system and do the work. He found ways to do tasks easier and some other shortcuts. But that is OK as long as you do the work and do get the grades.