Please branch and build libev-epel in epel10 The perl-EV package BuildRequires the libev-source package, which is not available in any RHEL 10 repo (including CRB).
Have you tried requesting libev-source to be added to CRB? We had a similar request [1] for libev-devel recently which was successful. If such a request for libev-source is rejected, I will provide this subpackage via libev-epel. [1]: https://issues.redhat.com/browse/RHEL-55297
Submitted as https://issues.redhat.com/browse/RHEL-94337