Hey

I would suggest you to go for the field in which your're interested.In your case you belong to PCM stream,and as you have mentioned that you have got good marks in JEE Mains 2020.But your interest lies in Civil Services Examination field,so i would suggest you to go for BHU for BA Hons(Social Science).It will help you a lot in CSE because there courses are some how related to courses that you will study further in CSE.

I Hope This Information Helps

Best Of Luck!!!