hi,

see gate stands for graduate aptitude test for engineering, it conducts by different IITs  in each of the year. there is many discipline available as gate paper which you have to choose. after getting valid gate score by securing the cutoff score you may apply for different iits, nits, state university and government as well as private colleges for m.tech course.  gate score holders are eligible to get 12400 stipend per month from aicte while pursuing full time m.tech course. however as per gate 2021 information, there is no particular stream as planning included. however candidates who have passed or in final year of  btech course of 4 years or diploma + btech of 3+3 years or msc courses or 4 years or 3 years bachelors degree courses are eligible to appear in gate from any of the stream. there is no restriction to chose gate paper, but during the admission of m.tech course Institutes has certain criteria for admission. so choose the course accordingly. https://gate.iitb.ac.in/papers.php

now coming  to government job there is few opportunities from planning stream since the most psu recruitment comes for civil, electrical, mechanical engineering.

hope it would help.