Alarm clock background does not go dark, looks light grey and glows in a dark room

I have the iPhone 11 and tried the "Alarm Clock for Me" app and it's turning out not to be. When I leave the screen on at night, I slide the dimmer down and the letters and number for the time and weather get dim but the black background looks like a bad tv where the black levels bleed light and look grey. So, the information gets dim but the background glows when it is supposed to just be black and blend in with the dark room. Can't use the app, too bright, I restarted the phone like an other post said to but no change. I have the dark setting and the wallpapers are dark, however I guess just using a black background that isn't a picture doesn't work on the iPhone 11? Any suggestions on what the iPhone 11 is capable of, seems it should be able to make a black background without an OLED. any suggestions to the app developer?