X11, according to wikipedia (https://en.wikipedia.org/wiki/X_Window_System) is "a windowing system for bitmap displays, common on UNIX-like computer operating systems."
Gnome is a desktop environment that relies on X11.
You are probably also talking about KDE, which is does similar things as gnome but is different.
You can use X11 but you'll need a desktop environment if you want to make it user friendly.
The choice is whatever you like.
Check out https://kali.training for the kali book, to get started with using linux.