I tried to upgrade from F30 to F32 without doing updates first, and I got:
gnome-software[2045]: not handling error download-failed for action
refine: failed to refine distro upgrade: Failed to download gpg key for
repo 'fedora': Curl error (37): Couldn't read a file:// file for
file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-32-x86_64 [Couldn't open file
/etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-32-x86_64]

And I am thinking... well, if we could have gnome-software (maybe even
dnf) to update fedora-gpg-keys.noarch before trying to upgrade to the
next version, it would make it more likely to succeed.

This is not just about gpg keys, there are many packages which are necessary to update first. Their list is dynamic, even during release lifecycle. That's why dnf recommends people to first perform a system update, and only then do a system upgrade. We failed to convince gnome-software maintainer to do the same: