[NAME]  No. Currently the only XPS laptops that offer that BIOS option are the XPS 17 models, and then only when optioned with the top-end GPU for that model. With the XPS 15, you will still be able to use the NVIDIA GPU to accelerate content on external displays, but only through NVIDIA Optimus. However, that may be sufficient for whatever you’re doing. And just fyi, even the regular WD19 or WD19S can run dual QHD from an XPS 15 9510. You don’t need a WD19TB/TBS for that with that particular system, although that will give you the option to upgrade to triple QHD or dual 4K.
I understand most docks render the display using the Intel GPU.  Is the 9510 capable of rendering the display via the NVIDIA GPU?  I would like to run two 2K displays and make use of my NVIDIA GPU for the output.  I just ordered a new XPS 15 with the NVIDIA GeForce RTX(TM) 3050 Ti 4GB GDDR6 [45W].  Am I correct that there is a BIOS setting that will allow me to force the NVIDIA GPU to be used for the display output when using the WD19TB dock?
Does the Dell XPS 15 (9510) use the NVIDIA GPU when dual-displaying 2K (QHD) 
over a WD19TB dock?