IES

Hello,
Only B.Tech graduates can apply for this exam. But, CS students can not apply, if they study the syllabus of other branches then they can also apply for it. All the best.

Yes, you can in fact clear IES Mains exam with CSE branch but you have to focus on another branch's subjects and clear the IES exam.

Diploma holder students are not eligible to apply for NITs. You can appear for JEE Main exam to be eligible for JEE Advanced exam. You can take admission in IITs but in 1st year of engineering.

For this, the eligibility is that you should hold a graduate degree in engineering. You should be a B.Tech only then you can fill for the job.

https://www.onlineengineersacademy.org/ese/
another one is byju's you can join classes.

As per UPSC, any government official applying for IES/ ESE will get the age relaxation even if he/she is already working on a post which is considered of a higher officer cadre. There is an age relaxation for the ones who have worked with any government organisation on contractual basis for a period of 3 years or more.