Hello aspirant !!

I am hoping that you are doing well. As per your mentioned query , see jee mains is an national level of exam so by doing practising from RD Sharma only is not enough. First you have to clear your concepts and then try to solve ncert first then after that i would like to recommend you cengage book for the maths. As you do many conceptual questions , you have clear your concepts more.

I hope this will be helpful for you.

All the best !!