So let's go! I was able to install GNOME along with the Plasma KDE and apparently everything is working normally. For my surprise installed GNOME 40 instead of 3. I will use for a while and see if there are really no problems.
For some reason Bisarro, I have Fedora 34 installed on another partition of another HD that I have in the notebook, and he "pulled" some of the settings I had there, apparently at least.
Until then I would recommend the GNOME installation along with KDE Plasma, but I am a beginner user and I do not have much property to evaluate this.
Thank you all what you answered and helped! I installed as follows:
sudo pacman -S gnome-desktop
sudo pacman -S gnome-shell
sudo pacman -S gnome (install all)
