AlbertoGP, thanks for your report, I followed the guide of those sites you posted, in fact the files for the screen savers were missing, I don't know why they disappeared since they were there before the installation of the modified Kernel to enable Navi 10. Maybe by default this Kernel needs to have them installed and so it doesn't have them. I ran the command: yum list | grep -i xscreensaver, he gave me a list and from that list I tried to install all those files it brought back. Some of them were present and some were not and I installed them. The screen savers are finally back, the only problem is that it puts them as files in the settings and I had to group them all in one window. Then he downloaded a lot of them and I had to remove a lot of them because there were really too many. Anyway, I solved it, thank you very much.
Xlinder I looked where you went but I didn't find anything, the problem was they were just missing.