How do I design an A/B test for cart abandonment solutions?

I've been losing sleep over our cart abandonment rates. Every month, we're seeing roughly 70% of potential customers add items to their cart but then disappear without purchasing. Our ad spend is substantial—we're talking $5,000 monthly on Meta ads—and watching potential revenue evaporate is killing me. I've tried generic pop-ups, generic discount codes, but nothing seems to stick. Our team keeps asking, 'Why are customers so close to buying but then ghosting us?' We know our products are solid, our pricing is competitive, but something in our conversion funnel is fundamentally broken. I need a systematic, data-driven approach to understand and solve this. It's not just about throwing random tactics at the wall; I want a methodical A/B testing strategy that can reveal exactly what psychological triggers or technical friction points are causing customers to bail at the last moment. This isn't just a marketing challenge—it's directly impacting our bottom line, our growth trajectory, and frankly, my stress levels.