Have a Shop look at it . this thing has no motion pictures on it.

It's quite blind.. and did not have my morning coffee waiting. ~o)

Index shift , rear, the foundation is getting the derailleur hanger aligned.
in a plane parallel to the wheel (and thus the cog ).

big to little , is return spring pull .. if it hesitates it can be the cable stiction in the housing..

new stuff for both.. Die drawn cable is slicker.