on the client machine, I have 

```
services.borgbackup.jobs = {
  compose = {
    compression = "zstd";
    encryption.mode = "none";
    environment = {
      BORG_RSH = "ssh -i /.key";
      BORG_REMOTE_PATH = "/run/current-system/sw/bin/borg";
    };
    group = "users";
    paths = "/data/compose";
    repo = "user@ip:~/backups/subrepo";
    startAt = "minutely";
    user = "user";
  };
};
```