My brother is a student of CSE at IET Lucknow, so I think I can give you some information regarding the CSE branch at the institute.
CSE is such a branch in which students excel even if they do not come from a well-known college. Doing well in CSE does not wholly depend upon the college name or the infrastructure.
Alumni - achievements:
The students of the CSE branch at IET Lucknow perform well in all fields, be it GATE, CAT, or placements.
Placements:
Here is the recent placement highlights for IET.
Highest CTC | 36 LPA |
Median CTC | 5 LPA |
Major recruiters | Amazon, Code Nation, Barclays, etc. |
So, opting for CSE at the IET branch will be a better option than taking a year drop for JEE. You can keep preparing for JEE side-by-side with college.