1. Install our app Releasit Cash On Delivery from the Shopify App Store here: https://apps.shopify.com/cash-on-delivery-fee
2. Go on the "Limit COD" page of the app
3. Enable the option "Hide cash on delivery for gift cards"
4. Done! Now Cash on Delivery will not be visible if the order contains a gift card in Shopify checkout
If you need help or you have any questions don't hesitate to contact us from the app!