Shopify Developer Needed for Extension Completion

I need an experienced Shopify app developer to complete the last 10% of a custom app. The app embeds interactive widgets on the storefront via theme app extensions (app blocks).
Everything is built but the authentication flow isn't fully connected, so the app blocks don't activate properly.
What's Done
Remix-based Shopify app with Vite, Prisma, Shopify CLI
Express backend with OAuth routes, auth status, widget config API
Two Liquid theme app extensions (inline + modal modes)
Admin dashboard UI with connect/disconnect flow
Webhook handlers and database schema
What's Needed
Fix Shopify OAuth — configure credentials, test session auth end-to-end
Wire up the auth flow to the extensions — so app blocks load correctly after merchant authenticates
Debug & test — full install → auth → add blocks → verify widgets flow on a dev store
Clean up project structure (two sub-projects with some duplication)
Requirements
Experience building & deploying Shopify...