Create a Cross Platform Android-iOS App on React Native

We want to build a Cross Platform Android-iOS App on React Native
It's an application intended for a group of notaries.
The application will allow the calculation of monthly bank credit and interest for the purchase of a property.

The contents are managed from the Wordpress backoffice of the site.
The Wordpress API is active for the call to content.

The particularity is in the management of loan / fee calculations.
The rules are set by a JSON file interpretable with MathJS from an Excel file (attachment).

Here is the mockup: https://projects.invisionapp.com/share/6DZMHCM4QNH#/screens/439533945

These informations will be retrieved from the wordpress website using the Wordpress API :
- Team name and contact = https://projects.invisionapp.com/share/6DZMHCM4QNH#/screens/443190473
https://www.lillaz-burtet-coste-mougel.notaires.fr/l-equipe/

- Blog / News = https://projects.invisionapp.com/share/6DZMHCM4QNH#/screens/443699885
https://www.lillaz-burtet-coste-mougel.notaires.fr/actualites/

- Contact = https://projects.invisionapp.com/share/6DZMHCM4QNH#/screens/443190471
https://www.lillaz-burtet-coste-mougel.notaires.fr/contactez-nous/

We are looking for an expert who is 100% available. You must be able to make the functional application identical to the model (perfect pixel). The developer must be sensitive to details and UI/UX because we want the model to be 100% respected down to the smallest detail.
This project is urgent and we want to have a daily update.

Thank you for giving us your best offer and your shortest time.
Our budget is 500-700USD and deadline 17th January

Thank you.