I have heard that pursuing B.Tech is just a waste of time and it has no job opportunities. Is it true?

All are rumours. Many students get the campus placement doing B.Tech only. In my college also, my seniors were getting a good package. The package they got in my opinion was sufficient as they were just freshers only. So if you want to pursue your aim (if it is related to engineering), then you must

See every year, the total engineering graduates are 15 lac approximately out of which only 2-3 lac get the decent job and all other are just for the sake of degree. Some go to start their own start-ups and only a few of them have to search for the job.