cmd tools are latest and sdk is right as my device requires API 31 and sdk needs to be compatible with that API. The problem is not in building its when files are getting transfered to the android device and running it on that device. I am past the build problem. You can check my past edits for that.
edit1: I think i will consider this solved and post a new querry for the descriptor file as technically the problem of uknown error has solved.