Those aren't trivial problems to solve in a traditional REST framework either. In GraphQL, having one whole query delivered upfront means the server can do som

Those aren't trivial problems to solve in a traditional REST framework either. In GraphQL, having one whole query delivered upfront means the server can do some clever query-planning and app-level caching to efficiently fetch its required data. REST endpoints can't do that, since the queries will be spread across multiple network requests.