Hi student,

No, it is not at all necessary give both JEE Main Paper 1 and Paper 2. If you wanna go for Architecture(B.Arch/B.Plan) then, only giving paper 2 will work for you.

Refer here for more info - JEE Main 2021 (April/ May) - Postpones, New Exam Dates, Registration, Admit Card, Result, Syllabus, Pattern (careers360.com)

To check your chances in different colleges, you are required to use JEE Main College Predictor Tool:- https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!