What is the Amplify backend best practice for adding calculated fields to GraphQL?

I am using Amplify's GraphQL backend, which works perfectly for generating standard CRUD operations.

However, what if I want to add a calculated field to the model?

For instance, I want to make a query that fetches a set of prices, and some of those prices are in my DynamoDB table, while others will come from an API call to a third party.

I can see two options from the Amplify docs:

• Modify the existing query resolver lambda pipeline, which entails writing a bunch of VTL boilerplate - exactly the kind of work I think Amplify is designed to automate
• Make the query with the @function directive, but then we don't get all the nice benefits of Amplify's generated pipeline, including auth and so on

Neither of these is ideal, or makes for a great developer experience. Let me know if you have a better way!