Project: Email Builder Integration for Materio Admin Panel

I am looking for an experienced Frontend Developer to integrate a modern Email Builder into my existing Materio Admin Panel (Next.js / React). Goal: Email templates should be created and managed directly from the admin panel without requiring programming skills. Required Features: Drag-and-drop email builder Image upload directly inside the admin panel Management of multiple email templates Desktop and mobile preview Light and dark mode support Test email functionality Database storage for templates Support for variables such as: customerName orderNumber deliveryTime totalPrice Preferred Technologies: GrapesJS Unlayer React Email MJML Important: Please do not send generic portfolios or screenshots. I would like to see real references, including: Video demonstrations Live demos Admin panels with similar functionality Previously implemented drag-and-drop builders Please also explain your exact role in each referenced project. The goal is to build a professional, maintainable solution that can be managed and expanded later without requiring developer assistance.