I made a script with documentation on https://github.com/freekdk/GenPDSDM to generate an email server on openSUSE Tumbleweed and Leap 15.5 and 15.6 with support security options for SPF, DKIM and DMARC. It can be used on several architectures, a.o. x86_64 and aarch64. It replaces more or less the mail module in YaST. Now this script needs to install the requested packages from two additional repositories in OBS.