Greetings mynightime,
If you are having difficulty with the brightness or color temperature on your iPhone, follow the guidance found here:
Adjust the brightness and color temperature on your iPhone, iPad, or iPod touch - Apple Support
"Adjust brightness and color temperature in Settings
- Go to Settings > Display & Brightness.
- Drag the slider to the right or left to adjust the brightness.
From here, you can turn on Dark Mode, which is designed to make the screen easier on your eyes. Dark Mode uses a dark color scheme that works system wide, including with the apps that come with your device and with many third-party apps.
True Tone,* which is on by default, uses advanced sensors to adjust the color and intensity of your display to match the ambient light, so that images appear more natural.
If you turn off True Tone, the display keeps color and intensity constant, regardless of changes in the ambient light.
You can also turn on Night Shift, which adjusts the colors of your display to the warmer end of the spectrum—making the display easier on your eyes. To adjust the color temperature to be warmer or colder, go to Settings > Display & Brightness > Night Shift and use the color-temperature slider."
Take care.