Smudges can be cleaned off unless they happened from a liquid source getting on it that may be harmful to the screen. Have you tried 70% or less rubbing alcohol on a microfiber cloth or lens cleaners for glasses or camera lenses? Do not use alcohol directly, moisten a microfiber cloth with a little and gently rub the affected areas.
I think OP may be saying that the smudges are permanent. This phenomenon was noted on the S24U, where the oleophobic coating had worn off over time. But that was happening around the one year mark. If this is what's happening to the screen on the S25U after a month, it sounds like a potential warranty issue to me.
