Mate you are so far off the range with all the theory complicating it.
For gods sake it's simple
THRUST CONTROLS THE SPEED
PITCH CONTROLS THE PATH
In nearly all modes except Climb and Open descent where the ONLY WAY is for the Elevator to directly control the Pitch as the thrust is fixed.
Yes PITCH AND THRUST effect each other AND WORK HAND IN HAND, no arguments there, however in swept wing Airline transport category Jets there can be no other way. It's been this way since the advent of the Airline Jet.
Please don't complicate it anymore than that with your science books professor classroom theory.....it's not Rocket science.
I've been successfully flying these things for 25 years all over the world in rain hail typhoon snow storm safely and correctly according to the check and training departments of 3 highly safe World standard Airlines that follow Manufactures guidelines WITHOUT problems ever.
If me or my 3 Airlines were doing it wrong it would have been picked up and corrected before this.
You my friend have the bull by the horns.