Sure they do. My current phone’s bump is completely leveled out by the case.
Mine isn’t. I want my case to also protect the camera glass, which means it needs to be really thick, which is worse than the bump IMO.
My current case is the Spigen Liquid Air Armor, which I like a lot because it doesn’t make the phone very thick, but it still has the annoying bump.
They make the contrast smaller because they don’t go over the bump. Also they can integrate it more seemlessly than this sharp 90 degrees angle.
You can get cases like that, but then open yourself up to damage to the bump. I personally use the Spigen Liquid Air, which is relatively thin and protects the bump as well, but it does nothing to minimize the bump.