Thanks for the info. So when i've installed kde with command $ dnf
groupinstall "KDE Plasma Workspaces", i couldn't use it, but after i've
removed it i've installed like this $ dnf install @kde-desktop
Then all worked well, the idea came from here
https://fedoraproject.org/wiki/KDE
I discovered that KDE was faster then gnome, and all the apps opened
faster and so on, and it was a big surprise for me, i wasn't expecting
it, but i removed it, because i did not liked the idea behind it, even
if gnome still have a lot of work in front of it, i prefer to be closer
to the cli. for me 1 screen isn't enough so gnome make's it very easy to
switch between them, i could also have shortcuts in kde to, but it
wouldn't be the same.