NIT

You have a decent AIR in JEE Mains and you can get lower branch in top NITs like:

1. NIT Nagpur 
2. NIT Surat
3. NIT Delhi 
4. NIT Bhopal

The specific branches you can go for in these NITs are listed below-

1. Electrical Engineering 
2. Mechanical Engineering 
3. Electronics and Communication Engineering 
4. Information Technology 

With a rank 21,000 in JEE Mains for the EWS category, you can get below NIT campuses:

1. NIT- Warangal
2. NIT Raipur
3. NIT Kurukshetra
4. NIT Surathkal
5. NIT Delhi
6. NIT Trichy
7. NIT Durgapur
8. NIT Puducherry

In all these campuses, there are various courses you can join including B.Tech CSE.

I hope it will help. 

Below are the NIT Colleges based on 82,000 CRL rank:

1. Integrated B.Sc. + M.Sc. in Life Science at NIT Rourkela
2. B.Tech. in Mechanical Engineering at NIT Nagaland
3. B.Tech. in Civil Engineering at NIT Arunachal Pradesh
4. B.Tech. in Metallurgical and Materials Engineering at NIT Srinagar
5. B.S. + M.S. in Chemistry at NIT Agartala
6. B.Tech. in Mechanical Engineering at NIT Mizoram

I hope it will help. 

The ROI of NIT Goa is quite good as the total tuition fee for its flagship BTech course is INR 5 lakh whereas the package offered to BTech students can be as high as INR 26 LPA.  Increase or decrease in the seat intake has not much impacted the quality of education the college provides to students. The college does not descriminate students while providing placement assistance. Outstation or not, opportunities are same for everyone. In the end, during placements, students skills play a crucial role in fetching good jobs. 

Yes, your improvement results in March 2025 will be considered for admissions in IITs and NITs for the academic session of 2025

BITS Hyderabad is a private college, whereas the NITs are government-run technology institutes. The entire tuition fee for BE degrees at BITS Hyderabad is INR 19.94 lakhs. While the tuition rate for BTech degrees at NITs approaches INR 5 lakh. Candidates seeking admission to an NIT must have a valid JEE Main score. Candidates can, however, apply for admission to BITS by taking the institute's BITSAT exam.

The highest and average BTech packages offered during the 2024 placements at VNIT Nagpur were INR 64 LPA and INR 12.10 LPA, respectively, with a placement rate of 65.26%. With a placement rate of 50.41%, the top and average packages for M.Tech placements were INR 64.67 LPA and INR 8.19 LPA, respectively.

Placements at NIT Delhi are competitive. With the maximum package at INR 46 LPA and the average package at INR 10.054 LPA, NIT Delhi recorded an 88.8% placement rate in 2021. In 2021, the average package for the Computer Science Engineering (CSE) branch at NIT Delhi was INR 12.2 LPA. Even while NITs generally face criticism, notably in relation to infrastructure and educational quality, they nonetheless provide good placement prospects, especially for students studying computer science. Among the best technical universities in India are the National Institutes of Technology (NITs), which include NIT Trichy, NIT Rourkela, and others.

No, you can not get admission to any NIT with 70 percentile in OBC category in JEE Main. 

The minimum percentile for NIT (2024) -

General - 91%ile

OBC - 88%ile.

SC - 82%ile.

ST- 74%ile.

To check for the cutoff in which you are eligible, the candidates are advised to visit: JEE Main Rank Predictor 2024: Calculate JEE Rank From Percentile/Score.