What a tangled web. No wonder it took three years to produce the report.
The bottom line is this accident was not caused by differential power, it was caused by the crew electing to continue to repeatedly fly an approach when the the conditions were not suitable and critically to fly below approach minimums without the required visual references.
If you read the report thoroughly, you will find that it was indeed caused by differential power, due to a fault in the sensing system for the engine power which was not picked up during maintenance because the full test was not carried out. When the thrust levers were moved back past the gate, the fault produced a negative torque in one engine which caused the aircraft to bank sharply 40 degrees to the left. The PF then attempted to correct this by pushing the levers forward and then overcorrected to the right. You are correct in that the aircraft was far too low at the point and so the roll to the right caused the right wingtip to impact with the ground. However, the actual cause was the differential in power between the two engines.