Are there other options (repos) for getting current versions of Postfix using dnf on a RHEL system?
fwiw, use existing pkgs from https://src.fedoraproject.org/rpms/postfix for 'Fedora ELN, if that fits your needs or rebuild & package from those sources, or your own tweaked/modified .spec, on your own COPR (https://docs.fedoraproject.org/en-US/infra/sysadmin_guide/copr/), specifically for your chroot of choice Fedora COPR certainly a variety of EPEL chroots, including 9, https://communityblog.fedoraproject.org/epel-9-is-now-available/ i regularly rebuild the rawhide sources, which only slightly/ocassionaly lag new Postfix releases, for F35 for production use; works a charm.