It was my first time to apply a NVIDIA graphics card to my homebuilt Linux machine.

Thus or independently a trouble happened.
No output on display, connected by a HDMI cable, was shown. Aka blank screen. It was in not only LightDM but also Xfce desktop after login. It always happened around the display manager, and, however, often around the desktop.
What was not critical seemed critical in that my time killed increased gradually... 🤕

The distro of my computer was Arch-based Artix Linux.
Arch linux helped me gently again.
I ran it according to the official documentation about NVIDIA:

# pacman -Sy nvidia

Happily ever after 🦔