As this is a work in progress, I’m going to add rather than edit.
In the example of the room, it works well if the room is empty. But if you have stuff in the room, like a table, you will then have shadow depending on where the light is directed. If you limit yourself to just an overhead light, there will be a shadow underneath. If you have track lighting, you will have a smaller set of shadows. Yet, even these shadows are not very dark, but gray. They will quickly go away by adding light from another perspective.
Realize, however, that the more ‘junk’ you have in the room, the more little areas of shadow and even darkness there will be. If you want a light room, you need to clean out the junk, and keep only what is needed. And boy do we all carry around a lot of junk! So, as we increase our light, we also need to do some housecleaning, further reducing the shadows within.