Hi,

There is no as such best course to clear UPSC CSE Exam. As you do not want to pursue B.TECH Course, you can join B.SC/BCA/BA courses in various specializations. In UPSC Syllabus, the subjects are mainly humanities oriented. So, you can assist your preparation for UPSC by taking up the Humanities field, preferably BA(General). You can choose subjects such as Political Science, Geography, History ,Economics as offered under the course. These are one of the core subjects in UPSC CSE exam. At last, you should pursue your graduation by seeing your area of interest. As you have asked, this study pattern of pursuing diploma then graduation will never hamper your career as such. You can make use of the following mentioned links for knowing more about the exam.

UPSC CSE Syllabus: https://competition.careers360.com/articles/upsc-ias-syllabus

UPSC CSE Preparation: https://competition.careers360.com/articles/how-prepare-for-upsc-ias

UPSC CSE Exam Pattern: https://competition.careers360.com/articles/upsc-ias-exam-pattern