Web App Migration to Updated Stack

Project Summary:
Note :: Most - Importantly i will not share my code and you have to work with me remotely
I'm working on a legacy web application built with:
React v16
Gatsby v2
Node.js 14 (used in AWS CodeBuild)
Due to AWS deprecating Node 14, I need help migrating the entire app to:
Node.js 22
Latest stable React
Latest Gatsby (v5+)

What I’m Looking For:

A developer who has hands-on experience in:
Migrating large-scale React + Gatsby apps across major versions
Resolving dependency and build issues
Working with AWS CodeBuild or similar CI/CD tools
Modern JavaScript practices (ES6+, Webpack, Babel)

Tasks Include:
Upgrade React 16 → React 18+
Upgrade Gatsby v2 → Gatsby v5+
Ensure compatibility with Node.js 22
Fix deprecated packages/polyfills (e.g., babel-polyfill, object.assign)
Update gatsby-node.js, plugins, and GraphQL queries as needed
Ensure AWS CodeBuild uses updated Node version
Full test the build and deploy pipeline

Deliverables:

Fully working build using Node 22
Production-ready Gatsby build with latest dependencies
Documentation of all changes made (Git commits + summary)

To Apply:

Please include:

Examples of past Gatsby/React migrations
Estimated timeline and availability
Familiarity with AWS CodeBuild or similar CI/CD tools