To disable dynamic checkout buttons for products with fees:
App embed settings:
In your Shopify admin, go to Online Store > Themes.
Find your theme and click Customize.
Click Theme settings.
Go to the App embeds tab.
Find Magical Fees and click to expand the settings.
Make sure Hide dynamic checkout buttons when fees apply is turned it on.
Click Save.
Product template:
In your Shopify admin, go to Online Store > Themes.
Find your theme and click Customize.
Open the drop-down menu at the top of the page and select Product.
Choose the product template used by products with fees.
Select the Buy buttons block.
Make sure Show dynamic checkout buttons is unchecked.
Click Save.
Cart template:
Navigate to Online Store -> Themes
Click ... -> Edit code
Navigate to Sections -> main-cart-footer.liquid
Find and remove the following block of code:
{%- if additional_checkout_buttons -%}
<div class="cart__dynamic-checkout-buttons additional-checkout-buttons">
{{ content_for_additional_checkout_buttons }}
</div>
{%- endif -%}Click Save.
This will prevent customers from bypassing fees at checkout.