3585 official VGA driver broken? Display switching off.

I am helping a friend with their Isnpiron 3585 (FRF71W2) - a brand new Ryzen 5 2500u machine.

It has a clean Windows10 Pro 64bit install with all the updates as of today 11.03.2019, the latest Dell BIOS (1.4.0 dated June 26 2019), Dell firmware udate for the SSD, Dell AMD Raven Ridge chipset driver, etc. everything from the Dell support site except the AMD VGA driver, because it causes a major issue.

By default,Windows 10 recognizes the GPU as a "Standard Microsoft VGA" and that works fine at 1080p 60 Hz, but obviously in a limited fashion (e.g. no secondary display available).

Installing the AMD Raven Ridge Graphics Driver from Dell's support site causes the main built-in display to either turn very dimm, with no brightness controls available and then randomly switch off, or completely switch off during boot, once windows started loading. Interestingly, one can connect an external monitor via HDMI and that will still work even in clone mode.

This is the official driver I've tried:

Version: 25.20.15030.4 ,A01

Last Updated Date: 14 Aug 2019

File Name: AMD-Raven-Ridge-VGA-Driver_RV8J7_WIN_25.20.15030.4_A01.EXE

File size: 354.6 MB

As this failed, I've tried the latest official AMD drivers from AMD's site. same issue, main display switches off during boot. I have tried both Adrenalin 2019 Edition 19.9.2 and Adrenalin 2019 Edition 19.10.2. The Radeon settings app will show the two montiors and device manager will list two montiors as well, but tha laptop's screen remains black, completely switched off.

Most annoyingly, the latest Windows Update force-installs the newst AMD driver which kills the computer (this is how they found out the issue and called me to help), so I had to disable all automatic driver updates via Windows Update.

Could the GPU be broken, or is there a compatibilty issue with these drivers. Does Dell have an archive with their older VGA drivers for the laptop? They only show the latest, so I cannot install anything else.