Omnibus installation - Accesing PostgreSQL DB for dashboard

I have GitLab running self-hosted with the Omnibus packages. I’m using mostly the default settings, so the DB access is done through sockets, not TCP/IP.

I’d like to connect [Metabase])( to GitLab’s database in order to create some dashboards displaying aggregated health data of our company’s project (how many of the projects have CI configured, how many MRs are being rejected, etc.)

Is there anyone doing something like that? Is it possible to create an additional postgres user with read-only access to the DB, to prevent Metabase from damaging the data?
What’s the recommended path to do it?

I briefly considered doing this through the API, but did not find a way to gather the data I need.