Hello Utkarsh 

The cutoff for EWS category i.e 78.2174869 is the qualifying cutoff for JEE Advanced. For admission to NITs, IIITs and CFTIs, seats are allotted on the basis of ranks in the JEE Main exam. 

JEE Main admission cutoff and qualifying cutoff are different. You can refer to the article for detailed information-

https://engineering.careers360.com/articles/jee-main-cutoff

Also, Reservation for EWS category has been provided for the first time by NTA therefore it would be difficult to tell you about your chances as previous year cutoff for EWS category is not available for reference.

However, according to your rank, you might have chances of admission to Engineering colleges through state level counselling.

Hope for the Best.

Good Luck!