Precision 7530 built-in monitor not active when external monitors are connected

I've been running Ubuntu 20 with two external monitors and nvidia drivers for some time, until one of the monitors died and I got a 27" Dell monitor replacement.

Now only external monitors work when nvidia drivers are installed ( tried versions 390, 440 and 450), the built-in monitor shows Dell logo and "Press Ctrl+c to cancel all filesystem checks in progress". When I uninstall nvidia driver built-in monitor works, but not external ones. Dell support is not helpful as the laptop originally came with Windows.

I like Ubuntu and Dell (I have owned more than 7 different Dell laptops), but all this issues with Linux and external monitors are just pushing me towards MacBooks. Not sure if XPS Linux users have a similar experience...