Hi Eslabonmx05,
Would you be open to a workaround that you create a placeholder shipping rate? (ie. create a shipping rate named “Select a delivery option”). I have added a feature recently to my app which the express button will always be hidden when a placeholder shipping rate is selected, as long as the customer has not selected their desire shipping method, the express buttons will not show even when they go back to information page.
My app name is Yagi Express Payment Hider (https://apps.shopify.com/yagi-express-payment-hider) , you can give it a try, there’s an “Advanced Option” that utilize a placeholder shipping rate, that might suit your needs.
Hope this can help!
Regards,
Axel Kee