Removing the Chinese text "未写入google key和tee key" watermark on the screen
Download Minimal ADB and Fastboot on the computer

Plug in the phone into the computer, but keep the phone on

On the computer, open the terminal/command prompt

Enter these commands
adb devices
adb shell
pm list packages
pm uninstall --user 0 com.mediatek.factorymode


Restart the phone and the watermark will be removed