Issue with rendering a simple low poly scene. Render is warped and deformed

You have a Subdivision Surface Modifier attached to your room, with the number of subdivisions set to 0 for the preview, but 2 for the render. If you want the render to be the same as the preview, turn down the number of subdivisions for the render. However, if 0 subdivisions is what you like the look of, you might not need the modifier at all, or if you still need the "floor" subdivided, consider using "Simple", as opposed to "Catmull-Clark".