Auditing & Migrating backend architecture (AWS Amplify)

Auditing current use of AWS technology
Cognito for accounts & logins
DataStore for offline data persistence
S3 for file Storage
Lambda
I'd like a review of our current setup, incl. graphQL schema (advice on directives, relationships and auth roles), advice on AWS DataStore and whether our setup could result in users not accessing their data given a threshold of items in the backend.