I have a Samsung A8 2018 SM-A530W, which was purchased from a major Canadian carrier. It recently updated itself to Android 9 through a Samsung application.
Since that update, many of my applications are very difficult to read. In the case of Calendar and Clock, the contrast ratio between the text and background makes text illegible. In the case of the settings screen, transparency to the wallpaper does the same. I'm sure this isn't intentional, but I'm wondering what I can do besides reset my phone.
White text on an almost-white background makes the calendar impossible to read.
Gray text over a gray background makes the clock difficult to read.
Black text over a transparent background to the default Galaxy wallpaper makes settings difficult to read.