which one is better option between llb and btech in today's world ellaborate?

In this world, Law will exist forever and the Engineering as well as Technological advancements will also exist.

So there are no such possibilities that there will be a lack in job for both the fields. Now you will say there are a lot of Engineers/ LLB's who are unemployed. I would explain that.

The reason of unemployability is more about knowledge and less about opportunity. As the world is advancing, its in general a need for more associates to work in the engineering and development. But the lack in students are they don't focus on the coursework or they learn theoretically more than the practical stuffs. Engineering is applied field so you need to be aware about the practical skills/Industrial skills. But in India this lacks and thus majority students don't get jobs but you will evenly observe a lot of students getting jobs.

Similarly for LLB, many students don't focus on the argument and spoken skills. These way they lose there progressive attitude towards the career. But for this field also there are lots of employability in Private as well as Government colleges.

Thus, as you have seen that both the courses are great in terms of employability. The subject matter are different but both the course have values and will have demand in the future also.

I hope my answer helps. All the very best for your future endeavors!