ImageMagick is not in CentOS 8. I understand this is because it’s been removed from RHEL. I believe that it will be shipping GraphicsMagick instead. But now there are no packaages at all, and what are we supposed to do? Do not use NC on CentOS\RHEL8 at all for now?
[root@something ~]# dnf list all|grep -i magick
[root@something ~]#
As far as I know imagick is only needed for the theming app. If you do not need the theming app you could disable it in the admin-panel. The warning will then go away.