It seems that your Xiaomi 11T Pro is having some issue with the wallpaper. Here are some steps that you can try to fix the issue:
1. Try resetting the wallpaper to default by going to Settings > Wallpaper > Choose default wallpaper.
2. Clear the cache and data of the launcher app by going to Settings > Apps > Manage apps > Launcher > Storage > Clear Cache and Clear Data.
3. Check if there is any third-party app that is causing the issue. Try uninstalling recently installed apps one by one to see if the issue is resolved.
4. If the issue persists, try restarting your phone in safe mode. To enter safe mode, press and hold the power button until the power options menu appears. Then press and hold the "Power off" option until you see the option to reboot into safe mode. In safe mode, only system apps are allowed to run. Check if the issue is still there in safe mode. If not, it means that a third-party app is causing the issue.
5. If none of the above methods work, you can try factory resetting your phone. Make sure to back up your important data before doing so.
I hope one of these methods works for you. Let me know if you need any further assistance.
