Custom WooCommerce Freebie Popup Plugin

I'm seeking an experienced WooCommerce developer to create a custom plugin called “ABBA Freebie.” This plugin will enhance our checkout experience by displaying a branded freebie popup.

Plugin Requirements:
- Popup Trigger: Display the popup when the user is proceeding to checkout.
- Gallery Display: Freebie items should be shown in a grid view.
- Admin Control: Admin should be able to manually select freebie items from a product list via a settings page.
- Popup timed display – shows 1.5 seconds after loading the checkout page.
- Responsive product grid – 2 columns on mobile, 4 on desktop, smooth internal scrolling, user-friendly design.
- Admin Settings Panel – allows admin to enable/disable the feature, set expiration date, select categories, choose multiple freebie products.
- Seamless integration – On click, item is added to cart at zero cost; popup closes; sessionStorage prevents repeat offers.

Ideal Skills and Experience:
- Proficiency in WooCommerce and WordPress plugin development.
- Strong understanding of PHP, Javascript, and front-end technologies.
- Previous experience with creating custom popups and admin settings pages.

Please provide examples of similar work done.