Is it possible to add the --ed25519 option to opendkim-genkey? PR #101 merged in the upstream develop branch seems included in the archlinux community repo, and maybe it could be added to epel too... :-) https://github.com/trusteddomainproject/OpenDKIM/pull/101 https://man.archlinux.org/man/community/opendkim/opendkim-genkey.8.en
For the record, Archlinux moved opendkim to the extra repo and this is the manpage new link. https://man.archlinux.org/man/extra/opendkim/opendkim-genkey.8.en