Hi.. I have cleared Prelims 2020 and in 2019 I missed by one question. I think covering static syllabus is very crucial for UPSC Prelims as there are around 50 questions which are not directly from current affairs. For current related, solving test series for improving guess, option elimination works. Though questions are not direct still helps in right guess. So I think command over static syllabus and right guess strategy worked in 2020. So u can accordingly devise your strategy.