First off customization for the user interface has been improved drastically. Now you can just pinch the Home screen with 2 fingers to bring up the personalization settings and you can freely customize your widgets, transitions, icon styles and even wallpapers without needing to jump into the launcher settings.
Talking about wallpapers, you can now create custom ones based on the photo that you took on your phone. The special algorithm of ColorOS11 will reorganize and analyze the colours and generate creative wallpapers of different styles based on your image reference.
Then there's the dark mode which has been further enhanced in ColorOS 11. It offers three colour schemes - enhanced, medium and gentle, each with different level of contrast, allowing you to set the auto start and off time, and can even adjust to the sunrise and sunset.