After getting it to work under proxmox (transition went easier than expected and with zero problems) I finally have easy access to the actual host console without messing around with USB sticks to import key files.
I noticed that it will by default start an interactive version of the CLI on the host console where I can enter the cli commands directly.
I also found through forum posts the undocumented “login” command that will give me a bash shell on the host, so I can theoretically do whatever I want on the host OS, explore the docker environment from the host and even enter individual containers from there and don’t even need the ssh addon anymore because I can enter the entire system in “god mode” through a proxmox web console.
What I could NOT yet find ls the other way around: when I happen to be on a bash shell where I have access to the ha cli and the interactive cli is not running (for example a separate shell window opened from proxmox), I could not figure out how to start the cli in interactive mode. I can ecxecute ha commands without problems, but I tried “ha --help” and “ha cli --help” to look for any clues but I could not find any mention of a command or option to start it in interactive mode.