How do I calculate ROI on abandonment discounts?

As a Shopify store owner in the fashion industry, I've been wrestling with cart abandonment for months. My ad spend is solid, and traffic looks great, but something's breaking down in the conversion funnel. I'm seeing promising metrics—visitors browsing products, adding items to cart—but then they just... disappear. Every abandoned cart feels like money slipping through my fingers. I've tried generic discount codes, but they feel scattered and ineffective. I need a strategic approach to understand not just how many people are leaving, but WHY they're leaving, and how to bring them back without devaluing my brand or giving away margins unnecessarily. The real challenge isn't just throwing a discount at the problem, but creating a targeted, intelligent system that converts hesitant shoppers while maintaining the perceived value of my products. I want data-driven discounts that feel personalized and urgent, not desperate or spammy.