Lack of motivation can be a problem and I love 3b1b videos. However, if you want to truly learn, you still have to sit 30-60 hours on a subject to be able to solve problems. No motivation will replace that.
When you have limited time to learn as a student, you either have the smarts to learn in the limited time or you cheat.
When you have limited time to learn as a student, you either have the smarts to learn in the limited time or you cheat.