while the general Postgresql 13 from the Postgresql community will be EOL soon, Foreman and Katello assume you use the Postgresql versions provided by your distribution. In case of RHEL9 (and other EL distros), Postgresql 13 is the “Full Application Stream Lifecycle” version (see here) , which means it will be supported by RedHat (or your EL rebuild vendor) until the EOL of your OS major release. Since Katello is only supported on EL distributions afaik, that should apply to your Katello installation as well.