Even if the app is very basic, I had great learnings with asking for & displaying data using GraphQL. The advantages with having a defined data shape—that is strongly typed—works really well with Swift. It was also easy to structure my code as I knew explicitly what data I was asking for, and thus I did no over-fetching that could happen easily by using REST.
Consider GraphQL an alternative when building a type-safe bridge from client to server. There are already many clients available, getting you quickly up to speed to test it out.