Prem Malkani

It seems you want to know what Is suitable for you and you are looking for answers outside! On the one hand, it's a good thing that you are seeking fundamentals.

To study is to equip yourself with adequate information but at an academic stage, the objective is to get a good score as well. This criterion can be fulfilled by extensive reading, understanding, writing by which you demonstrate how much information your brain has processed, retained and reproduced, i.e. appearing for exams and the results.

So at this stage, work backwards. Ask yourself how well you are prepared for the exams (set a non-negotiable target score then maybe doing a pre-study test to know your level of preparedness). Once you know how far you are from your target, use your strengths to design a method by which you will be able to cover that distance. The solution is within you, while the standard tools (google/youtube etc.) may help. Still, you know how your mind understands and retains the information, i.e. pick examples from your memory and figure out familiar ways to memorize your subjects. The span of attention is very subjective. I have taught students who learn in 60 mins and can retain it for six months. It's all about memorizing the way it suits you. Try the POMODORO technique, should be a good lead. I hope this helps.