Previously, the only setting added was the Mouse Sensitivity. The value was just changed and saved in the Camera script, as it was only needed in there. Since the Camera was destroyed when switching or reloading Scene, the Settings would thus be reset to its default value.
To fix this, I introduced a GameManager singleton into the game, where settings and other values can be saved to, which can later be written to and loaded from a file, if necessary.
Other than that, the Slider also didn’t really give a good indication of what the Sensitivity value was, but we could not get rid of it due its handy slider feature. Therefor, I added an Input Field to the side, where the value of the slider is displayed, as well as where you can enter a value and the slider will update to that exact value.