how to set nvidia gpu card as primary card

I have installed steam on Ubuntu 20.04.5 and I'd like to use only the dedicated GPU in games, not the UHD Graphics 620. The games that I try, such as Tropico 6, keep the Intel UHD GPU as main.

I see the NVIDIA GPU on the info of the OS, but there are some problems running some commands (like nvidia-settings or nvidia-xconfig).

$ lshw -short | grep -i display WARNING: you should run this program as super-user. WARNING: output may be incomplete or inaccurate, you should run this program as super-user. /0/100/2 
display UHD Graphics 620 (Whiskey Lake) /0/100/1c.4/0 
display GP108M [GeForce MX150]

$ lspci -nn | grep -E 'VGA|Display' 00:02.0 VGA compatible controller [0300]: Intel Corporation UHD Graphics 620 (Whiskey Lake) [8086:3ea0]

This command does nothing:

$ sudo nvidia-xconfig
WARNING: Unable to locate/open X configuration file.

Package xorg-server was not found in the pkg-config search path. Perhaps you should add the directory containing `xorg-server.pc' to the PKG_CONFIG_PATH environment variable No package 'xorg-server' found New X configuration file written to '/etc/X11/xorg.conf'

Using sudo nvidia-settings I get the error bellow:

(nvidia-settings:4655): GLib-GObject-CRITICAL **: 11:28:24.506: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

ERROR: nvidia-settings could not find the registry key file or the X server is not accessible. This file should have been installed along with this driver at /usr/share/nvidia/nvidia-application-profiles-key-documentation. The application profiles will continue to work, but values cannot be prepopulated or validated, and will not be listed in the help text. Please see the README for possible values and descriptions.

Here are screenshots of the OS info and the driver I use:

What can I do?

Laptops which have two GPUs (e.g. Intel and Nvidia) usually use a hybrid setup, so the Nvidia GPU does the display setup, and the Intel GPU outputs the display. Lately, Ubuntu releases seem to have confused which GPU does what. The "default" GPU gets changed depending upon settings, and suddenly, games can't run anymore on the Intel GPU. You may see the GPU association by:

xrandr --listproviders

The default (0 GPU?) changes when you change a power option from Performance (which selects the Nvidia GPU as default) to Balanced (which selects the Intel as default). Simply select "performance" for the power option.

For running a program without changing power options, you may prepend the program with:

__NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia <progtorun>

This will switch the assignment of GPU so they are used the way they should be.