Install Android 10 for Dark Mode Improvements
Night Mode, which arrived on board Android Pie, gets some upgrades in Android 10.
Android 10's version of Night Mode is called Dark Mode. It's the same name Google uses with the stock version of Android.
In addition to the name change, there are some features that might convince heavy Night Mode/Dark Mode users to upgrade to Android 10 right away.
Dark Mode includes enhanced image, text, and color adjustments for day and night environments. You'll also get darkened wallpapers, widgets, and alarms while Dark Mode is active. This is a big deal because it means you won't be blinded by a bright wallpaper (if you're using one) every time you go back to your home screen when Dark Mode is on.
If you want to set when Dark mode darkens the wallpaper, you can do so by opening the Settings app, tapping on Display, tapping on Dark mode, and then toggling the Apply to wallpaper option on.