I am using ldap2pg to import users from my domain into postgres as roles, so people can automatically login to pgadmin/postgres using their domain credentials.
You are importing users from your domain into Postgres as roles so they can login into Postgres, and if you wish to authenticate the users for the pgAdmin login using LDAP, you can enable the Ldap authentication into pgAdmin. Refer https://www.pgadmin.org/docs/pgadmin4/5.4/ldap.html for the setup information.
Is it possible to setup pre-defined connections for a database on the server side? We are using the web-server instance of pgadmin4, version 5.3. My instance of pgadmin4 is dedicated to my postgres database, so it would be nice to save users the step of having to define the single required connection they would need to, to access to the db.
You can achieve this through Shared Server using the Server dialog.