iOS lets you turn on a red filter that disables the green and blue channels. you can set it to turn on by triple tapping the home button (or I'm guessing the back for new phones). This is the one thing I really miss after switching to Android. The red screen is fantastic for reading at night, really easy on the eyes.
Cf.lumen has this feature (yes, true red colouring, not just a yellow tinge like night shift), but it requires root and it's not updated anymore. (you need to find the 3.72 beta version online for it to work on Android Q)
Yeah Android has some features and apps in this space. This iOS mode is an accessibility feature. I guess for some people a pure red screen helps them see it better?
This feature is not intended as a "night mode", it's very extreme. It also makes anything that has no red channel in its color disappear (although this is rare). I found it's a better night mode than actual night modes. But it's best if you're just reading text, for video or games it's probably too extreme.
