Career

Give preference to pharmacy over biotech. Biotech is growing in India, BET at a nascent stage as of now. It will have great future in India as well as abroad. So, if you are planning to go abroad for higher studies in biotech, there is good scope in US, particularly. Pharmacy has great future. Here and abroad!

You can consider following branches:
Computer Science
Information Technology
Software Engineering
ECE
Civil

Time is very precious. Put extra hard work, accommodate more time for preparation. Don't drop 1 year just for coaching. Paralleling you need to do something which is achievable at the end of the year.

A detailed list of Courses which you can pursue after 12th for Arts and Humanities Students are mentioned at the link provided below:
https://www.shiksha.com/courses-after-12th/arts.

You can choose to be an academic lecturer in a dental college or more options are open after MS. So you can even consider going for Masters.

Yes, petrochemical engineering is a good career. There are lots of opportunities for petro chemical engineers. The future of petrochemical engineers is bright.

RWTH AACHEN
TU Munich
University of Stuttgart
KIT
University of Hamburg
Above are some of the best university for embedded and automation.

After 12th, you can take up B.Com and do the CS course alongside.

https://www.google.com/amp/s/www.shiksha.com/science/articles/amp/job-options-after-bsc-degree-know-salary-packages-blogId-13469
I hope the link aids your query.