Flutter Developer for Admin App Enhancement

I need a skilled Flutter app developer to add a "manual request money" feature to my existing admin app.

The functionality should include:
- Enter amount manually
- Select a user from a list
- Simple and minimalistic design

Ideal skills and experience:
- Expertise in Flutter development
- Experience with payment integration
- Strong UI/UX design skills for minimalistic interfaces
- Ability to deliver ASAP

Please share your relevant experience and estimated timeline.