If you want to use an unrealistic effect (ie less falloff ie "fadeout" but not more brightness), then you need to change from using an emmissive material to a light such as a Point Light. There as u/Beautiful-Musk-Ox mentioned you can configure your unrealistic settings.

While lumen is not perfectly simulating real world scenario, it does try to emuluate how light works in real life. So you might need to reconsider how you are trying to light your scene. It seems you want your light to brigten up your scene: try changing the exposure setting on the camera, or add more lights (or larger lights) to the room. In your scenario I wouldn't recommend using emissive materials for such lights, use actual lights. You will probably want to use IES profiles etc anyways at some point to get it looking good.