How to Change the “Donate” Button for Style 4 Donation Forms

TL;DR
Use the wcdp_donate_label filter to change the button text in style 4 donation forms.

Example

To change the button text from Donate to Continue, you can add the following snippet to your site:

add_filter('wcdp_donate_label', function($button_text) {
    return 'Continue';
});

This filter only affects style 4 donation forms and donation forms on product pages.