If enabled to display it, when you change the FoV the value will be displayed on screen for sevreal seconds, in the same way other things like power, flaps setting, etc. are.
When you alter the FoV, it does not change your position in the cockpit. While it may appear so, as you zoom in you are not getting nearer to the sight. Altering the FoV is identical to changing the zoom setting on a camera lens; it makes everything near and far change in scale identically.
In your screenshot of your monitors, note how the effect is of a 'window' which is very much wider than it's tall. This horizontally elongated view is reminiscent of the view through the small window, or slit, on a tank. Hence the 'tank slit view', as I call it.
This is quite fine for more sedate flying, but in a turning fireball the very significant loss of FoV in the vertical is an awful handicap. Even a 120 degree horizontal FoV will not cover as much vertically as a 16:9 display at 85 degrees. The stretched aspect ratio, augmented by the gnomonic distortion of a 120 degree FoV, will result in a still restricted view angle in the vertical.
Incidentally, I might mention that I wrote software to generate custom star charts for publication in magazines and books, using a variety of projections. And so the distortions imposed by stereographic, orthographic, azimuthal equidistant and gnomonic projections is well understood.