The provider_name is fixed to oauth2_basic and the provider_uid would be whatever you fill in oauth2 json user id path.
You just have to set that site setting to the path of the id based on what your provider returns. The plugin uses this json path to fill in the provider_uid, so if it’s currently empty or a path that doesn’t exist, the value will be nil.
From your json above it looks like the value should be sub.