Example of how to filter the thank you page text based on the select payment method used on the EE_Transaction

tw_filter_thank_you_text_based_on_pm.php

<?php

add_action('AHEE__thank_you_page_overview_template__top', 'tw_filter_thank_you_text_based_on_pm');
function tw_filter_thank_you_text_based_on_pm($transaction) {
    $payment_method = $transaction->payment_method();
    
    if($payment_method instanceof EE_Payment_Method) {
    	if($payment_method->type() == 'Invoice') {
    		add_filter('FHEE__thank_you_page_overview_template__order_conf_desc', 'tw_filter_thank_you_text_for_invoice');
        }
    }

}
function tw_filter_thank_you_text_for_invoice($original_text) {
    // This filter is call if $event_type is true above.
    return 'This is some custom text set if there is a custom value';
}