Podman socket access denied for backup container

Hi, I wanted to try this image with podman-compose but the rcb backup command fails with permission denied. I already tried to change the permissions of the socket to rw for all users that didn't help.

It worked by adding privileged=True to the backup container here: https://github.com/lawndoc/stack-back/blob/e11842b44b6d9b146b1234fc90fce83a146a2d44/src/restic_compose_backup/backup_runner.py#L20-L30

Am I doing something wrong in my configuration?

I am running Podman using podman machine on macos.

compose.yml

services:
  stack-back:
    image: ghcr.io/lawndoc/stack-back:v1.5.3
    restart: unless-stopped
    privileged: true
    environment:
      RESTIC_REPOSITORY: /srv/restic-repo
      RESTIC_PASSWORD: test
      DOCKER_HOST: unix://var/run/docker.sock
    volumes:
      - /run/user/501/podman/podman.sock:/var/run/docker.sock
      - ./backup:/srv/restic-repo

Error message from backup container:

Traceback (most recent call last):
  File "/restic-compose-backup/.venv/bin/rcb", line 10, in <module>
    sys.exit(main())
             ~~~~^^
  File "/restic-compose-backup/restic_compose_backup/cli.py", line 23, in main
    containers = RunningContainers()
  File "/restic-compose-backup/restic_compose_backup/containers.py", line 400, in __init__
    all_containers = utils.list_containers()
  File "/restic-compose-backup/restic_compose_backup/utils.py", line 39, in list_containers
    client = docker_client()
  File "/restic-compose-backup/restic_compose_backup/utils.py", line 29, in docker_client
    return docker.from_env()
           ~~~~~~~~~~~~~~~^^
  File "/restic-compose-backup/.venv/lib/python3.14/site-packages/docker/client.py", line 94, in from_env
    return cls(
        timeout=timeout,
    ...<3 lines>...
        **kwargs_from_env(**kwargs)
    )
  File "/restic-compose-backup/.venv/lib/python3.14/site-packages/docker/client.py", line 45, in __init__
    self.api = APIClient(*args, **kwargs)
               ~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/restic-compose-backup/.venv/lib/python3.14/site-packages/docker/api/client.py", line 207, in __init__
    self._version = self._retrieve_server_version()
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/restic-compose-backup/.venv/lib/python3.14/site-packages/docker/api/client.py", line 230, in _retrieve_server_version
    raise DockerException(
        f'Error while fetching server API version: {e}'
    ) from e
docker.errors.DockerException: Error while fetching server API version: ('Connection aborted.', PermissionError(13, 'Permission denied'))