Provided that you have key-based SSH access from the container to the host, you can add a terminal profile to your remote settings (run command Preferences: Open Remote Settings (JSON) (Dev Container) to open them):

Use with AI{
    "terminal.integrated.profiles.linux": {
        "bash (Host)": {
            "path": "ssh",
            "icon": "terminal-bash",
            "args": [
                "user@host",
            ],
        },
    },
}

This will get you an according bash (Host) entry in your "Add Terminal" drop-down menu: