Field of view (fov) is probably what you’re referring to. Some games give an option to change fov in the menu, I’m not sure if MSFS does. It’s basically the same function as zooming in or out with a camera, and is independent of screen resolution. However, it is quasi-related to screen shape. For example, a display with the same horizontal resolution but higher vertical resolution would cause the game to show either more image vertically or less horizontally - which I suspect is the source of your confusion. But since just about every monitor these days has standardized around 16:9, it’s not a big issue anymore.