which topics I should struggle for mains to get 60 marks out of 300

Hi

You can easily score 60 marks by doing the chapters with highest weightage which are listed below

PHYSICS

*Modern Physics -20 marks
*Heat and Thermodynamics-12 marks
*Optics - 12 marks
*Current Electricity- 12 marks
*Electrostatics- 12 marks
*Magnetics- 8 marks

CHEMISTRY

*Transition Elements and Coordination *Chemistry- 12 marks
*Periodic table and Representative Elements- 12 marks
*Thermodynamics And Gaseous State- 8 marks
*Atomic Structure- 8 marks
*Chemical Bonding - 8 marks
*Chemical And Ionic Equilibrium - 8 marks
*Solid State And Surface Chemistry - 8 marks
*Nuclear Chemistry And Environment - 8 marks

MATHEMATICS

*Coordinate Geometry-20 marks
*Limits, Continuity and Differentiability-12 marks
*Integral Calculus:- 12 marks
*Complex numbers and Quadratic Equation :- 8 marks
*Matrices and Determinants:- 8 marks
*Statistics and Probability:- 8 marks
*Three Dimensional Geometry:- 8 marks
Vector Algebra:- 8 marks

You can get chapterwise weightage for all the chapters for each of physics Chemistry and Maths by going through

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

Thankyou