See if you targeting USA for your UG studies then I would recommend  you to study harder for SAT. See the pattern of SAT and JEE MAINS & ADVANCED are different. So as you have less time you should focus more on the thing that is directly related to your aspiration. If you are preparing for JEE MAINS and ADVANCED then first complete the most weightage topics which you can get visiting the link provided below.

For the JEE MAINS chapterwise weightage, visit the link below:

https://engineering.careers360.com/articles/jee-main-syllabus-weightage

To know more about JEE ADVANCED Chapterwise weightage, visit the link below:

https://engineering.careers360.com/articles/jee-advanced-syllabus-weightage

Concentrate more on your SAT preparation and focus on the JEE MAINS & ADVANCED for the problem solving part, the foundational strength you will get by solving MAINS and ADVANCED problems will give you a more strength in your journey laterwards.

To know more about the career in Physics, visit the link below:

https://www.careers360.com/courses/physics-course

I hope this answer helps. All the very best for your future endeavors!