Was there infinite light, boundless darkness, or nothing at all existing before the creation of the universe?

Kind of, none of the above.

By our best models the creation of the universe is exactly that, the creation of the universe. Both space and time, as we experience them start there.

So, let’s look at this from another view point. Can you view all of space from an outside point of view? Well, not in any way we can experience. Also, we need the passage of time to witness things. even a photo is a point in time, so without time we aren’t setup to witness things.

So, to experience before the creation of the universe requires two things that don’t exist. Ergo, from our point of view there is no “before” the creation of the universe.