B.Tech

See, you cannot expect CSE or any other core branch in a government college, try out for some private university exams.

As per last year's trend, cut-off ranks for disciplines in Tezpur University were 20,000-40,000 for general category so it will be bit difficult to get a seat. Also, check the below link:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=cconnect&utm_medium=CR_JEECP&utm_campaign=8030745

lEMJEE 2018 is being conducted by the reputed IEM group for admission to B.Tech/ BCA/ BBA/ BPT/ M. Tech/ MCA/ M.Sc/ MBA courses of IEM (Institute of Engineering & Management) Group and UEM.
One can also admit through wbjee or jeemain rank.

Kindly visit the link mentioned below:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=shiksha&utm_medium=email&utm_campaign=clientmailers

It will be released after the declaration of Advanced results.

Sorry to say, but you can't get admission in DTU for biotechnology unless you crack JEE mains exam with a good rank.

Check the below link for colleges based on your rank:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=8030745
Also, do check for state engineering colleges accepting JEE Mains score.

I would suggest doing B.Sc. As nowadays, IIMs do not prefer B.Tech or BE degree holders.
Even there might be a discrimination against you during the interview due to an engineering background, but it's okay if you want to make your career in the IT field, all you need to do is have some work experience. Else, I would suggest you one more thing, if you are capable of doing your graduation from Germany then you will have a chance to get the job in Germany after graduation. If you want to stay in India go through B.Sc and meanwhile prepare for CAT as well.