I just finished setting up my new Mail-In-A-Box, since my old one was still running on ubuntu 18 and I was not able to upgrade MiaB.
I set up the new box by using OpenTofu/Terraform, so all the infrastructure needed will be set up automatically for me. Additionally I can re-execute OpenTofu whenever I need a new box.
I just wanted to share the repo with you, maybe it will help some of you: GitHub - JonasTaulien/opentofu-mailinabox: OpenTofu configuration for setting up a Mail-In-A-Box.
Just open an issue in the repo, if something does not work for you or if the instructions are not specific enough.