You ask if I am familiar with a pulse-jet, with its spring-loaded louvres. I am, but are you familiar with a ramjet, which has no forward walls at all? How do you explain that?
The engine designer uses a subtle blend of pressure, velocity and temperature distributions, something along the line of Bernoulli's theorem. The highest pressure, is actually just aft of the compressor, and before the combustor cans or rings, not in the combustion chamber.
Speeding gas up drops its pressure, while slowing it down increases it. That is why there are components with names like nozzles and diffusers. Diffusers expand the gas, slow it down, and drop the static pressure. Nozzles tend to do the opposite, and direct the flow in the desired direction.
In spite of the general acceleration of gas in all of these engines which creates a forward force, there is an element in rocket engines and afterburners where the acceleration of the gas is not the only force. There is also an element, especially in rocket engines, where the gas exerts pressure on the divergent part of a convergent/divergent nozzle which als propels it forwards.
Of course I believe in Herr von Braun, and of course I recognise the use of rockets. I'm not so sure that you have interpreted them correctly.
Again, I refer you to "The Jet Engine" by Rolls-Royce, especially the Chapters on "Basic Mechanics", "Working Cycle and Airflow", "Afterburning" and "Performance".
I have only relayed what they say, so if you have a better idea, then let them know
This is a good discussion, because everyone truly seems to have a different interpretation. Even the folks who make the things have good arguments about it from time to time, but don't let that put you off flying!