Bigger deck angle causes gravity to pull harder on the load
Well, no. The engines provide thrust, and you can trade this either against increasing airspeed and/or climb rate by varying pitch angle with your elevator.
For any given speed, there is a pitch angle where your aircraft will no longer accelerate, and going past that angle your aircraft will decelerate. For an aircraft having a thrust to weight ratio of one, this angle is 90 degrees.
So what this all means is that the load inside the aircraft gets pulled exactly by the same force regardless of your pitch attitude.
(Apologies for polluting this thread with entry level aeronautical concepts)