Is it possible for human to use ancient weapons in Kaliyuga? Can humans in Kaliyuga really control it? How much time does it take to understand those weapons?
Yes. It occurs a bunch of times in the Bhaviṣya Purāṇa. Such as:
He recalled the divine Raudraastra and threw it which struck the heart of Baalakhaani and likewise Alhaad and sons of king Parimala, made them fainted.
(happens on page 39)
As to why the supernatural is so hard to find right now; it is unclear. It is also unclear why the recent appearance of transmissible cancers seems to break the trend (maybe because it confuses literally everyone the first time they hear it).