Thank you for reaching out. Unfortunately, at this time, there is no clear or easy way to specify additional charges for specific payment methods natively within Shopify. However, there is app called Order & Product Fees that may be able to help with this—one of the latest reviews it received was from a merchant who claimed they used to set up additional fees for specific payment methods, so it may well be an option. The app comes with a 14-day free trial so you can install it and test it out to see if it's a viable option for you.
Victor | Shopify Social Care