To customize the controversial Messages app design in iOS 17, you can follow these steps:

  1. Jailbreak your device: Customizing the Messages app design requires jailbreaking your iOS device. Jailbreaking allows you to access and modify the device's software, enabling customizations that are not officially supported by Apple.

  2. Install a package manager: After jailbreaking your device, you will need to install a package manager like Cydia or Sileo. These package managers provide access to various tweaks and themes that can be installed to customize the appearance of the Messages app.

  3. Search for Messages app customization tweaks: Use the package manager to search for tweaks that allow you to customize the Messages app's appearance. Some popular tweaks include changing the font, colors, and layout of the app. You can also explore alternative Messages apps that offer more customization options.

  4. Install the chosen tweaks: Install the desired tweaks or themes from the package manager. Once installed, the customization options will become available in the Settings app or through the tweak's dedicated interface.

  5. Customize the Messages app: Follow the instructions provided by the tweak or theme to customize the appearance of the Messages app. This may involve changing settings, selecting new graphics, or modifying the user interface.

Please note that jailbreaking your iOS device can void its warranty and may expose it to security risks. Customizing the Messages app design is a personal preference, and the search results provided do not offer a direct solution for customizing the app. Always consider the risks and benefits before proceeding with jailbreaking your device.