Precision 7530 dim brightness problem

Hello to everyone,

I bought a Precision 7530 and I had to reinstall Windows for many reasons.

I have an annoying issue with brightness: I can't dim it with Fn+ArrowDown nor with using Windows Display settings.

I tried several workaround such as:
- updated BIOS to 1.12.1 (that mention "Fixed the issue where the LCD brightness cannot be adjusted." in enhancements list, BTW)
- disabled and re-enabled Intel UHD 360 from Device Manager
- uninstalled and reinstalled Intel's driver
- updated all the system with Dell Precision Optimizer

I ran out of ideas.. What can I do to resolve this issue? my eyes are close to vaporizing because of the extreme screen's brightness

Thank you in advance for your support, I'm looking forward for your answer
Best regards!!