from fedora rawhide logs, I see it may parse releasever to 38 (which may be rawhide) in fedora rawhide chroot, but I am not sure!!
- Status code: 404 for https://download.copr.fedorainfracloud.org/results/topazus/fedora-copr/fedora-38-x86_64/repodata/repomd.xml (IP: 2600:9000:208f:ae00:4:bbc1:1840:93a1)
the above URL may be https://download.copr.fedorainfracloud.org/results/topazus/fedora-copr/fedora-rawhide-x86_64/repodata/repomd.xml, which the status code of URL is not 404.
The URL that errors out is this one: https://download.copr.fedorainfracloud.org/results/topazus/fedora-copr/fedora-38-x86_64/repodata/repomd.xml
Whereas the actual URL of the file is this: https://download.copr.fedorainfracloud.org/results/topazus/fedora-copr/fedora-rawhide-x86_64/repodata/repomd.xml
Have you tried the copr://user/project syntax? If that works, you could avoid hardcoding anything in the path.