How to Turn Off Auto Brightness on the iPhone XS

• Go to Settings
• Go to General
• Scroll down to Accessibility
• Scroll to Display Accommodations
• Toggle the switch for auto-brightness

Auto-brightness is on by default, but for those of you who would prefer to turn the feature off, you can do so—but Apple doesn’t make it easy.

Be warned that turning off auto-brightness may affect your battery. Apple also warns that long-term display performance might be affected.

Of course, these directions apply to any device running iOS 12, not just to the iPhone XS.

Article source: https://www.technobuffalo.com/2018/10/12/how-to-turn-off-auto-brightness-iphone/