+1 on the derailleur hanger.
Swapping out the rather flimsy OEM hanger on my bike with a quality one, made a big difference. I improved shift performance even more by investing in an alignment tool.
Maybe something is bent and not lining up properly. I have had three and they all worked fine. I had to bend some parts so components would line up properly. Look straight on from behind the bike to see if all looks lined up and straight and nothing looks twisted.
like most hanger tools it rotates both around the attachment point and the measuring rod. I am more pointing at the price difference between the stuff from Jason than on the usability and their "super-powers".
and yes I do know a few guys wrenching for the national cycling teams. And they do not use Abby tools, just a bunch of other brand (surprisingly not that many use American brands))