A lets B sign a NDA/NC and then shares its ideas.

How "broad"/"general" can these ideas be to not be considered confidential? E.g. the idea that A tells B is this: "Making an app similar to x but with a better UX and simpler design." without getting into details, how it can be done more intuitive/simpler.

Can this idea be protected by the NDA/NC without any details about how you could reach this goal?