Hi Éva,
It’s possible but this will require a plugin that can actually fetch the discounted price by coupon and be displayed in place of the default GP Premium cart.
You’ll need something like this PHP snippet:
This one removes the default GP premium cart and adds a custom one depending on what you’ve added as callback function
add_action( 'wp', function() {
remove_action( 'generate_menu_bar_items', 'generate_wc_do_cart_menu_item', 5 );
add_action('generate_menu_bar_items', 'gp_woo_custom_cart', 5 );
} );
And then you can create a sample function like this where you can add the replacement cart.
function gp_woo_custom_cart(){
//do your plugin's shortcode for displaying cart here.
}
Here’s how to add PHP – https://docs.generatepress.com/article/adding-php/