I’m talking about Fedora I do not know about RHEL .
In fedora you can list all groups include hidden groups like this .
sudo dnf group list hidden -v
sudo dnf group list hidden -v |grep -i gnome
to install group example gnome group .
sudo dnf group install “GNOME Desktop Environment”
or
sudo dnf group install gnome-desktop
or
sudo dnf install @gnome-desktop
The three command are the same.
Maybe you need later enable gdm.service(gnome display manager) and set target to graphical.target .
sudo systemctl enable gdm.service
sudo systemctl set-default graphical.target
Groups are defined in repositories see this link.
https://fedoraproject.org/wiki/How_to_use_and_edit_comps.xml_for_package_groups