I tried
sudo rm /etc/yum.repos.d/owncloud.repo
sudo rpm --import https://download.owncloud.com/desktop/ownCloud/daily/4.0/linux/Fedora_38/repodata/repomd.xml.key
sudo dnf config-manager --add-repo https://download.owncloud.com/desktop/ownCloud/stable/latest/linux/Fedora_38/owncloud.repo
sudo dnf update
and getting the same problem, it can only be solved by sudo rm /etc/yum.repos.d/owncloud.repo (results in owncloud-client 2.10.1)