What are the key metrics I should be tracking to measure the success of my abandoned cart emails? (e.g. open rate recovery rate)

As a Shopify store owner, I've been losing sleep over abandoned carts. Every day, I see potential revenue slip through my fingers – shoppers who were interested enough to add products but didn't complete the purchase. I've invested time and money in setting up abandoned cart email campaigns, but I'm struggling to understand if they're actually working. Are my emails even making a dent? I need a clear, systematic way to measure their effectiveness. I want to know not just how many people open the emails, but how many actually come back and complete their purchase. My ad spend is tight, and every recovered cart represents real money back into my business. I'm looking for metrics that give me a true picture of my email campaign's performance – something that goes beyond vanity metrics and shows me the actual revenue impact. I want to optimize my strategy, reduce cart abandonment, and turn those almost-lost sales into actual revenue.