Exam

First of all congratulations on securing such a good score. It would be difficult to get into MSRIT, but surely I would suggest you to try, who knows if your luck prevails. I would like to suggest you to look into BGS School of Architecture and Planning, Bangalore too.

Candidates shall be eligible for admission to the First Year of the Bachelor's Degree programme in Architecture or Planning if they have obtained at least 50% marks in aggregate with mathematics as a subject in the class 12th or qualifying examination. You should also have a good score in JEE Mains

You can refer to this link for details https://www.shiksha.com/exams/ktet.

Please refer to this link to get more insights of the colleges and branches. JEE Mains colleges:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
JEE Advanced colleges:
https://www.shiksha.com/b-tech/colleges/b-tech-colleges-accepting-jee-advanced-india. However, as per your rank, y

No, you can not get 10+2 certificate on the basis of your Diploma course.

Eligibility
Graduation degree in English with minimum 60% marks in aggregate
Admission Process
Entrance exam based or merit based.

If you were working in that gap, it won't affect. If you weren't a part of any industry, it will surely affect at the time of admissions.

Part time job gives you experience but I don't think it will get any benefit in job. You will also have get good marks in CMAT.