I know Ruby on Rails, and Shopify Polaris
You can check out my profile for similar Shopify app made using Ruby on Rails
➡️ For all my apps, I've used
⭐ Rails for the back-end (both Ruby 3 & Ruby 2.7)
⭐ Polaris (ReactJS) for the embedded front-end
⭐ Postgres for database storage
⭐ Heroku for hosting
⭐ Github for version control
⭐ GraphQL for communication with the Shopify APIs (mostly the Admin API)
Does your existing app fit that description (or most of it)?
Then look no further, because you just got yourself a reliable Shopify app developer
I can start working immediately, so contact me and we can start discussing that feature you want to add to your app, along with the bug fix you want to make