Disclaimer
Try at your own risk. I didnt do it yet…
Running
Run it from a text terminal Alt+Ctrl+F3.
Script
tee migrate-gnome-kde.sh << EOF > /dev/null
#!/usr/bin/bash
sudo dnf shell -y --setopt protected_packages= << EOI
swap fedora-release-workstation fedora-release-kde
swap fedora-release-identity-workstation fedora-release-identity-kde
run
remove @gnome-desktop
run
remove *gnome* *gtk*
run
install @kde-desktop-environment
run
EOI
sudo systemctl restart sddm.service
EOF
Source
https://discussion.fedoraproject.org/t/is-it-possible-to-switch-completely-to-kde-from-gnome/66747/5