I’ve tested AlmaLinux every way I could think of, and the way that seemed to work best was to install CentOS 8.3, install Virtualmin, install whatever other stuff I wanted to install, migrate the sites, and run the migration script. Doing it that way was flawless.
Other ways I tried were impersonating CentOS 8.3, hacking the Virtualmin install.sh script, and doing the AlmaLinux migration at various other points after installing Virtualmin. They all worked, sometimes with various farts and burps that needed to be stifled. But waiting until everything else was done was easiest and produced zero errors.
It’ll all be irrelevant soon as @Ilia and @Joe are working on native support in the installer. But it’s nice to know we have one solid replacement already. The AlmaLinux test box is still humming away nicely, with its chief complaint being boredom.
As an aside, Oracle Linux also works (although I didn’t test it as thoroughly). I also suspect that Rocky Linux will work. So we who still favor RHEL derivatives will have options.
Richard