Applying discount codes in the cart (prior to checkout)

I tried out 6 apps that promised to add a discount code validation to the cart but turns out 5 out of 6 had various issues with stacked discounts or free shipping discounts, or didn’t work at all. Decided to write down a detailed review of all of them here: https://appreviewhq.com/shopify-discount-app-review-2024. TLDR: the only app I found that supported both stacked discounts and free shipping discounts was https://apps.shopify.com/discount-before-checkout. Still crazy to me how this is not a built-in feature, and how many apps seem to get it wrong.