Can I find any moderate-size app that uses Meteor with Appolo and Postgres as an example? The Meteor guide and tutorials, as well as most well-known Meteor open source apps (wekan, telescope...) use mongo collections.

And since Meteor is a full stack framework, I would love to see a guide about how to best structure an app with Meteor and Apollo (I'm in the camp where I don't like to fiddle around with what's the best js stack. I'm happy to have the framework authors decide that for me, and get down writing my goddamn app)