Yes, if you are not getting Nit and IIIT you can take admission in state technology college and university which are government university for this you have to resister for your state level of counselling of engineering colleges and you have to fill your preferred choice of college and your favorite branch and then you will get seat in these colleges and report this colleges with your allotment letter and after verify your documents you will get admitted in those colleges. My best of luck to you

HELLO AJAY SINGH
Congratulations for your result and qualifying JEE mains.

since it is very difficult to predict the exact rank but we do have a backup> we have a formula to calculate the expected rank that is (100 – Total percentile) x 869010/100.

So according to formula your expected rank for present percentile for January session comes out to be 52140 . Now the expected rank might change depending on the no of candidates appearing the april session. For ex if 12 lakh candidate appear the april session then just replace 869010 by 12 lakhs. But if you score above 85 percentile then you have a very decent chance of qualifying jee mains.WIth the present percentile it might be difficult for you to get into TOP  5 NITS and getting CSE branch but you can do it and you have still a chance to prove yourself wrong because you still have a decent chance of writing JEE ADVANCE which can lead you into IIT.Since you have the potential just try to grab a percentile of above 99.6+ so that top NITS are i your hand.
But if you are curious to know that which college you might land into with your percentile then you can use the college predictor link which has following features;

JEE Main 2020 College Predictor

Know your college admission chances based on your JEE Main Percentile, Home State, Caste, Gender, etc

Including premium institutes like NITs, IIITs and CFTIs, many States/ Institutes accept admissions through JEE Main. Know your chances in states like Maharashtra, West Bengal, Delhi

Get your personalised JEE Main report with Top Predicted Colleges in JoSAA & State Level Counsellings delivered on mail

2.5 Lac engineering aspirants used Careers360 College Predictors

*B.Tech Companion*

Your one-stop B.Tech Counselling package with Full-Length JEE Main Mock Tests, 15+ College Predictors, a printed Almanac with 1000+ FAQs on Admissions & more

https://www.careers360.com/btech-companion

ALL THE BEST FOR APRIL AND ADVANCE!!