I make things that try to be quieter than the phone they run on.

A sleep and focus app. Warm light, slow sound, and a set of rules about when it is allowed to interrupt you, which is most of what makes it work.

The root half. Android can already tint a screen to candlelight and dim it below what the brightness slider allows, entirely in the compositor. It just refuses to go that far, because the limits are constants in framework-res. The module moves them, and refits the colour ramp so the new range is actually correct rather than merely permitted.

It also stops apps waking you: per-app permissions, quiet hours, and a watcher for the "we miss you" kind of notification. No Xposed anywhere.

Doesn't fit the theme above: it's a general LSPosed toolbox, not a calm one. A status bar clock you actually compose, per-app display density, notification rules that block a message before it reaches your tray. Beta, and every feature says on its own card whether it has actually been tested on a phone yet.

The thing I keep coming back to is that a phone screen is built for daylight and stays that way at 3am, and almost every fix for it works by laying grey over the top. Adding darkness is not the same as emitting less light, and your eyes can tell.

If any of it helped, a coffee is a kind way to say so. Telling me the PWM knee of your panel is worth more, though. It cannot be measured in software, only by a person looking at a screen, and it is the same for everyone who owns your phone.