As someone who recently did mtech from a 2nd gen IIT. Here is my honest opinion.
Ask these question to yourself.
1. Do you have a current job or upcoming which pays you somewhere above 10 lpa?
2. Would you be able to go to 20 lpa in 2 years?
3. Is networking easy for you?
4. Are you hoping to get a good college within the first attempt?
If you think you can go easily from 10 lpa to 20 lpa easily in 2 years than don't bother with the MTECH. Things you'll learn in the college are kinda irrelevant to the job market. You wuld need to practice a whole lot of DSA. See the average placement not the maximum of the colleges. The base of every company is going to be around 15-20. Few are exceptions, and so are the students who are selected for them.
If you are already earning with 15 lpa job, skip the m.tech focus on your skills.