IISER accepts KVPY score to provide admission in dual degree program BS-MS as it is not associated with B.Tech in EE whereas IIIT-H also accepts KVPY but they dont offer admission in EE in B.Tech as only CSE and ECE is available there. So I would say if you want to go for B.Tech in EE then better to focus on Jee main preparation as this would be the only way possible to get seat in your desired course. Some of the preparation tips are mentioned below -

1. Know the syllabus very well.
2. Read standard books once you are done with your NCERT as there are many books available in the market so it is advisable to use the books which make all your concepts clear and which are easy to understand.
3. Understand the weightage of topics properly.
4. Proper Revision plan should be followed.
5. Mock Tests and Practice Tests should be done as this will help you to learn time management skills and this will also make you familiar with the exam pattern.

Hope this helps!!!