Mobile & Desktop UI Designer

I am in need of an experienced UI designer to create visually appealing interfaces for both mobile and desktop platforms. The primary goal of the design is to enhance the user experience.
I have already made a web app using Flutter framework, but I want to improve the UI of my project. I am very confused about the UI, so I want you to make the ui using Figma or any other alternative and then I can code it myself, just need help in deciding the UI ( what should be the colors scheme , size, font, animations), as my project is subscription based project, so I want a very professional as well as bold UI.

I will showcase the project to it, then you can create the UI and then I can code it.

Key Requirements:
- Design for both mobile and desktop platforms
- Prior experience with UI design
- Understands the importance of user experience enhancement
- Ability to work with a bold and vibrant color scheme

Please be prepared to showcase your past UI designs to help me determine if you're the right fit for this project.

Looking forward to working with a talented designer!