I want to turn off dimming ios 27

Check Auto-Lock

Go to Settings → Display & Brightness → Auto-Lock.

• Set it to a longer duration, such as 5 minutes.
• If it is set to 30 seconds or 1 minute, the screen may dim shortly before it locks.

When the screen dims, which of the following happens?

• A. The screen becomes noticeably darker while you are actively using the iPhone, and the brightness slider remains at the same position.
• B. The brightness slider in Control Center also moves down automatically.
• C. The screen dims after a few seconds of inactivity, just before it locks.
• D. The screen dims randomly, especially while charging or using the phone for a long time.

This distinction will help identify whether the issue is related to automatic brightness, thermal protection, or display settings.

Display

Parts and service history

With iPhone 11 models and later, excluding iPhone SE (2nd and 3rd generation), using iOS 15.2 and later, you can go to Settings > General > About for the parts and service history of your iPhone. You can also find out if the display has been replaced. If the repair was done using genuine Apple parts and processes, "Genuine Apple Part" will appear next to Display.

• An Unknown Part  message will appear if the display installation is incomplete or if the display:
• Was replaced with a nongenuine display
• Was already used or installed in another iPhone
• Isn't functioning as expected

An additional message might appear that says "Apple has updated the device information for this iPhone." This means that Apple has updated the device information maintained for this iPhone for service needs, safety analysis, and to improve future products. 

These messages don't affect your ability to use your iPhone.

Learn more about iPhone parts and service history.

Get a Genius Bar Reservation and Apple Support Options - Apple

When you encounter issues with your Apple devices, the Genius Bar at Apple Retail Stores is the go-to place for expert assistance. The Genius Bar is staffed by knowledgeable Apple employees, often referred to as "Geniuses," who can diagnose and resolve a wide range of hardware and software-related problems. To ensure personalized attention and a convenient visit, Apple provides the option to schedule a Genius Bar Reservation.

Contact Genius Bar.

Manage Reservations - My Reservations - Apple

Take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support:

1. If you prefer face-to-face assistance, you can visit an Apple Retail Store. Apple Retail Stores are designed to provide a hands-on experience with Apple products and offer support services. You can speak with Apple specialists, known as "Creative Pros" in some locations, who can assist you with product-related inquiries or minor troubleshooting.
2. In addition to Apple Retail Stores, there are Apple Authorized Service Providers (AASPs) that are authorized to perform repairs on Apple products. AASPs are independent businesses certified by Apple to offer service and repairs for various Apple devices.
3. If visiting a physical location is not possible or convenient, you can seek support by contacting Apple Support. Apple offers various channels for support, including phone support, live chat, and email. The official Apple Support website provides information on how to reach out to Apple for assistance.

Finally, you can also start a repair log or track the status of existing repair -->  Apple Repair and Repair Status Check - Official Apple Support

In summary, Apple provides customers with a range of support options, including the Genius Bar Reservation system, visits to Apple Retail Stores or Authorized Service Providers, and various channels to contact Apple Support for assistance with their products. These services aim to ensure that Apple users receive the necessary help and support whenever they encounter issues with their devices.