Why are you so desperately defending 'Canon or the camera'? The connector in this 5D-4 is exceptionally 'stiff'. Nothing wrong there, just good to know if you want to connect a mic to the 5D-4. And that was what this thread was all about.
And THAT is the true solution here. Push that mic connector in REAL good. Only when your internal mic is NOT picking up any sound, you know that the external mic is connected properly.