Hi,
the socket connection type should be used for GSE based installations usually. The --socketpath argument must point to the socket provided by gvmd/openvasmd. We don’t have this path under control and different distributions use different paths. See for example the following topic
The other connection types are mostly for GOS 3.1 (TLS) and GOS 4 (SSH) on GSMs .
You need normal unix file permissions to be able to access the unix socket of gvmd/openvasmd. Therefore you can adjust the permissions, user and group of the socket via gvmd/openvasmd parameters. You should NOT run any python script as root user only to avoid caring about file permission settings.
We are currently in a process of writing (better) user documentation for gvm-tools. See https://gvm-tools.readthedocs.io/en/latest/ for a first draft.