Hi Ryan,

Not sure if it works on RHEL too, but I have tested DNF on CentOS :
https://seven.centos.org/2017/10/yum-4-is-available-for-testing/
Here you can see what happened, dnf got installed alongside yum :

sudo yum install centos-release-yum4

Installed:
centos-release-yum4.noarch 0:1-1.el7.centos

sudo yum --enablerepo=centos-yum4-testing install yum4

Installed:
yum4.noarch 0:2.6.3-11.el7

Dependency Installed:
dnf.noarch 0:2.6.3-11.el7
dnf-conf.noarch 0:2.6.3-11.el7
libcomps.x86_64 0:0.1.8-7.el7
libdnf.x86_64 0:0.9.3-8.el7
librepo.x86_64 0:1.8.1-1.el7
libsolv.x86_64 0:0.6.26-1.el7
python2-dnf.noarch 0:2.6.3-11.el7
python2-gpg.x86_64 0:1.7.1-0.el7.centos.1
python2-hawkey.x86_64 0:0.9.3-8.el7
python2-libcomps.x86_64 0:0.1.8-7.el7
python2-librepo.x86_64 0:1.8.1-1.el7
rpm-plugin-systemd-inhibit.x86_64 0:4.11.3-25.el7.centos.1

Dependency Updated:
gpgme.x86_64 0:1.7.1-0.el7.centos.1
rpm.x86_64 0:4.11.3-25.el7.centos.1
rpm-build-libs.x86_64 0:4.11.3-25.el7.centos.1
rpm-libs.x86_64 0:4.11.3-25.el7.centos.1
rpm-python.x86_64 0:4.11.3-25.el7.centos.1

sudo yum4 --enablerepo=centos-yum4-testing install dnf-plugins-core

Installed:
dnf-plugins-core.noarch 2.1.3-2.el7
python2-dnf-plugins-core.noarch 2.1.3-2.el7  

Regards,
Christian