Searching for that on pkgs.org , it looks like it’s available in the EPEL (Extra Packages for Enterprise Linux) repository: https://rhel.pkgs.org/9/epel-x86_64/perl-Text-Iconv-1.7-43.el9.x86_64.rpm.html
Rocky has an easy way to enable this 3rd-party repository: dnf install epel-release (assuming the Rocky Extras repo is enabled, which it should be by default)
Once enabled, DNF should be able to find the dependency.