Auto Applying Shopify Discount Code on Subscription Plans: Need Help!

Hey, can anyone help with an issue we have on our landing page. We have subscription and one-time selling plans, and an offer on subscription only, powered by a Shopify discount code. At the moment the code applies on click of the subscription module, but if the user doesn't actively select that then subscription is still preselected but the discount code is not added. Is there a way to make sure the code is auto applied for subscription but not OTP?