Site Changes - React and Node

I am looking for experienced developers to work on modifications to an existing website. The changes I need involve both front and back-end development using Node and React frameworks. I currently have an existing codebase I would need the developer to work from. The changes will likely require a knowledge of Node and React, as well as Angular to ensure compatibility with the existing codebase. I am open to ideas about how to best accomplish the necessary changes. Accuracy and attention to detail are paramount. This project is time-sensitive so I need someone with the experience to deliver these changes quickly and accurately. I emphasize that the project is under development and I am currently having some problems with delivery and corrections with the hired team. Right now it's simple items to be adjusted. It is not mandatory but some knowledge of Portuguese would be ideal, after all it is our language and it will be easier to apply the adjustments.