I tried duplicating one side of my armature and mirroring it to the other side with Shift+D, S, X, -1. It works except that in pose mode, the arm and the leg are not symmetrical to the other side. Is there a way to fix it other than manually replacing them? I really want to keep it clean. The rest position is ok though.
My file is here -
https://drive.google.com/file/d/13oPK4rJQuXMJ106jL1chpc0jwh5cdrmY/view?usp=sharing[][1]