That sounds frustrating. It sounds like you have gone through many of the steps in the Troubleshooting Digital Modes – digirig. Another thread you can check is Cables for Yaesu FT-891 where users focus on PTT rather than CAT control. It is a good place to start.
If you think something is misaligned with the audio cables, reseat them so they are firmly in place. The audio cable is TRRS, that goes into the Digirig and the miniDIN-6 goes to the Yaesu. If you think you may have bought the wrong version of the Digirig, open up the case and take a look at the configuration pads.
You are very close to a solution. Keep going!
73 Constrainted