Your ssh terminal output above, how did you ssh to get that? It appears you are in the OS filesystem and you need to define the ssh private key in the home assistant docker file system. The warning you posted seems to support that you don’t have the keys in the docker file system.
HAOS installs Home Assistant and any Add-ons in docker containers. That makes it convenient to upgrade by simply pulling the new docker container from Github.
By “Home Assistant Terminal” I assume you mean the Home Assistant VM in Proxmox. That is not the right location. Follow the guide I posted above; it has all the information needed to correctly setup the correct shell and command line entities.