Broke my rear derailleur a week ago along with the hanger.

On my Spark 720 year 2015, the old hanger said 142-RWS12 IDS-SL so I ordered a new one from eBay: https://www.ebay.com/itm/SCOTT-23528...-/291980522554

Bought a new Shimano XT RD-M786 derailleur from a local shop. Both say "Shimano RD-M786 VLA" in the recess.

The parts fit together but it's clear that the reach of the derailleur will never reach the largest sprocket no matter how the adjustment screws are set, so my suspicion is that I've got the wrong hanger for the frame+derailleur combination, despite the markings being the same as the old equipment. The derailleur can't reach as close to the wheel as needed.

Which is the correct hanger?