Hi, I have the same problem.
I found the manual on the Internet. I solved it as follows. Instead of “pm uninstall –user 0 com.mediatek.factorymode” I wrote to adb “pm uninstall –user 0 com.hct.factorymode, because “com.mediatek.factorymode” I cannot found.
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
