Avinash, the MHRD did announce that JEE Mains 2021 will be conducted with a reduced syllabus. And the official reduced syllabus hasn't been announced as yet. With reduction in the syllabus, the weightage, important topics might change. So at this point in time, the best thing to do is to stick to NCERT books and practise as many sample papers or mock tests you can get hold of. You do not want to have a strategy for an entire course  and then be told that few chapters aren't even necessary. But by sticking to NCERT books and Mock tests, you keep it simple and come back with a strong basic knowledge of the topics. Once the syllabus has been released, then you can focus on the more important and included ones.