2012 GMC Acadia - Second engine - same problem

It’s a long story about the engine light repeatedly coming, and after replacing many parts the motor catastrophically failed. After replacing the motor ($9000), within 1500 miles, the engine light has come on flashing three more times. Stopping and turning the car off and restarting, turns the engine light off.
The code indicates a misfire. Dwayne Lanes Arlington cannot seem to fix the problem. What wasn’t replaced that could be causing this after the motor was replace?

You are not receiving responses because there is near zero information to work with. Lack of info means what diagnostic codes were being set and so on and WHY the engine catastrophically died.

Catastrophic death of engine usually means lack of oil although severe overheating can also kill an engine.