Thank you all for your nice and helpful comments. Despite a couple of obstacles I managed to get the Ansible repository done to set up a new mail server on Debian Bookworm. Ansible helps me get a reproducible installation of ISPmail on fresh servers. And I could adopt a couple of good ideas from others forking my Ansible repository. You can already find the repository at https://github.com/Signum/ispmail-bookworm-ansible
Suprisingly little has changed between Debian Bullseye and Debian Bookworm. So I can copy most of the sections to the new guide. I have scattered collection of notes that I need to go through before releasing the final guide.
At least I listened to your suggestions to focus on the actual guide and not try to add new funky features in the first place. Yes, I’m guilty of overcomplicating things. So the guide will be released just as usual and I will add further features depending on my spare time and your helpful suggestions. I still haven’t given up on the idea of a proper web management interface. 🙂