CRM-ERP System Modification with Flutter

I need a proficient developer to assist in modifying an existing CRM-ERP system. The system is to be rebuilt with a Flutter frontend (mobile and web), PHP backend, and SQL database. My primary goal is to enhance the project for better performance and usability.

Key Functionalities:
- Sales Management
- Customer Relationship Management
- Project Management
- Budget Management

Ideal Skills and Experience:
- Proficient in Flutter for mobile and web development
- Strong knowledge in PHP backend development
- Experience in SQL database management
- Previous work on CRM or ERP systems
- Skilled in project and budget management modules
- Ability to integrate various functionalities seamlessly
- Previous experience submitting/publishing an iOS and Android app

Please note that due to missing information, specific modifications required in the system have not been provided. I'm seeking a reliable and experienced professional for this project. I am a developer as well but I'm on a very tight deadline. Please show me previous business/enterprise projects you've worked on.