I have brand new XPS 15 9500 with GTX 1650 Ti and latest NVIDIA drivers (460.89)
When I play a game (eg. Diablo 3) it uses integrated graphics card (GPU-0) and performs poorly (35 FPS max).
According to the benchmarks, the GTX (GPU-1) should be performing more then 110 FPS on this configuration.
Make sure the Nvidia driver came from Dell, not Nvidia. Dell customizes drivers for you exact motherboard. You will have problems if you install drivers from Nvidia. There is a new driver at Dell Downloads.
It is from Nov 2020.
This system is software-controlled -- verify you've chosen to run the game with the nVidia GPU in the Optimus control panel. Also bear in mind that ONLY the Intel GPU has a connection to the display on this model - the nVidia GPU is a coprocessor, not a discrete GPU, so the Intel GPU will always be active at all times.
I use the Dell driver for GTX now (452.41 / 184.108.40.20642) and the performance is still horrendous.
The FPS is capped to 33 FPS as if running on integrated Intel GPU even when I choose the lowest graphics settings.