Which Precison laptops support Discrete Graphics Controller Direct Output Mode ?

Hi,
I'm looking to buy a Dell Precision and I was wondering which of them supports "switchable graphics" ? 
The Precision 3581 I bought last year had two GPUs: and Intel Iris and an NVidia RTX 2000 ADA.
When I connected an external monitor, it turned out the HDMI/Displayport adapters were connected to the Intel CPU because the system used the NVidia Optimus technique which could not be overruled. 
I need a system where I can enable "Discrete Graphics Controller Direct Output Mode" in the BIOS so the HDMI/Displayport connectors are linked directly to the discrete GPU (Nvidia) without passing through the Intel GPU. 
On the Dell website, I found some references on Precision models that had this option:
* https://www.dell.com/support/kbdoc/en-uk/000183937/dell-systems-supporting-hbr3-specifications?lwp=rt
* https://www.dell.com/support/manuals/nl-nl/precision-17-5750-laptop/stradale_external_monitor_guide/check-the-graphics-options-on-your-computer?guid=guid-8c3354c0-fb20-482f-bf59-7f82ed4565a6&lang=en-us
Unfortunately, these models are no longer on sale.
So my question is: how can I be 100% sure my next system will be able to do this ?
Thanks in advance,
Tom