The solid-clien module looks more complete in abilities how to access solid PODS, but it’s written that it’s deprecated in the readme, although there is activity in the repo.
So all web operations should be done via auth.fetch as its written in
solid-auth-client is maintained and recommended for use. You should use it to read and write resources to a Solid POD. (There might come more resources/alternatives later on, but right now solid-auth-client hopefully covers your needs.)