There is no guide yet as we have to add Ubuntu 22.04 support (which requires PHP 8.1 support) in ISPConfig first before writing that guide. Just look at the documentation page at ispconfig.org, if there is no guide listed there, then there is no guide.
It would be also interesting to add Linux Mint to the list. They have a Debian LTS and Ubuntu LTS version. And in my option is the best Linux Distro. Because they are focusing on making Linux more simpler to use.
Linux Mint is indeed a nice Ubuntu Desktop variant. But Linux Mint is not really a server OS, so not sure if it makes sense to officially support it in ISPConfig. Nonetheless, it should probably work and be recognized as Debian or Ubuntu. Regarding Ubuntu 22.04, see updates in this thread: https://forum.howtoforge.com/threads/ispconfig-on-ubuntu-22-04.88848/