can't find your post on test-list, so I answer here
I did some days ago:
1.
sudo dnf upgrade --refresh
2.
sudo dnf install dnf-plugin-system-upgrade
3.
sudo dnf system-upgrade download --refresh --releasever=30
--setopt='module_platform_id=platform:f30' --allowerasing
- the above is ONE line with a blank between "=30" and "--setopt" -
4.
sudo dnf system-upgrade reboot
5.
sudo dnf system-upgrade clean