Build/Enhance a backend on AWS for mobile app

we have mobile app running using AWS As backend
Key components :
AWS api gateway , AWS Lambda functions (python / node.js)
Dynamo DB
SNS (OTP Based login)

- We currently have few api's running and want to add more with database operations .
- Need AWS Cognito expertise
- Nice to have knowledge on IAM roles and permissions
- Expertise in backend service development for mobile apps
- should be using best practices on OTP Login Authorization
- Manager User pool using Cognito
- Data base development (Relational and NoSql DB using Dynamo DB)
- Data Migration & Analytics
- Backend Architecture
Project Is hourly based pay (40hrs/week) with compensation upto 500 Rs/hr