I might be missing a trick. Some options, listed below, do most of the things and even those which the FAQ admits are beyond its scope. Amongst a multitude of alternatives, I have settled upon TwinkleTray for Windows. MonitorControl on macOS. OLEDify for iOS/iPadOS/Android, or just take a shot at one of the superb wallpapers from r/Amoledbackgrounds. As an example, in order to comprehensively test the display, I used DisplayTester on Galaxy S20, when I first acquired it. There are similar tools for other OS'.