Hello,

1. Every year the rank and marks for PSU varies. And in order to get into any PSU you not only need to clear the cutoff but also you need to score very high so that you have a good rank. I am providing you a link for previous year cutoff for various psu where you can find the gate score you need to score to be eligible for psu.

https://www.google.com/amp/s/engineering.careers360.com/articles/what-are-gate-scores-for-psu-recruitment/amp

2. After m.tech or phd if you want to have job in top psu, you need to give gate because on gate score if you are eligible you have to give their interview or some psu like BHEL also conduct their own exams so that you can take that and give interview and get selected.

Hope this will help you if you need more help you can ask.