Can I change the title of the payment gateway shown during checkout?

Yes, the “Card” text shown during checkout can be changed with many free translation plugins, such as Say What. In fact, almost any string can be changed by using the text domain woocommerce-payments.

Here’s how to change the “Credit card / debit card” text with Say What:

If you don’t want to use a translation plugin, you can try a simple code snippet:

function ah_change_credit_debit_text( $translation, $text, $domain ) {
	if ( $domain == 'woocommerce-payments' && $text == 'Card' ) {
		$translation = 'This text is different!';
	}
	return $translation;
    
}
add_filter( 'gettext_woocommerce-payments', 'ah_change_credit_debit_text', 999, 3 );

The result is the same either way.