php - Switch required/unrequired on Woocommerce Checkout Fields

one text

I am trying to add or remove some checkout fields when an user click a radio button or an other. I am creating two event listeners and trying to make some ajax request to change the status of the checkout filed - from required false to true.

This is my code:

jQuery(".radio_fizica").click(function() {
    jQuery('.factura_firma').hide();                                                        
});

jQuery(".radio_juridica").click(function() {
    
    jQuery('.factura_firma').slideDown();
    
    ajaxurl = '<?php echo(admin_url('admin-ajax.php')); ?>';
        jQuery.ajax({
        url: ajaxurl, 
        data: {
            'action':'example_ajax_request',
        },
        success:function(data) {
            console.log(data);
        },  
        error: function(errorThrown){
            console.log(errorThrown);
        }
    });                                                                             
});

And this is the php code in functions.php

function sv_unrequire_wc_phone_field( $fields ) {
$fields['billing_company']['required'] = true;
$fields['billing_company_code']['required'] = true;
$fields['billing_company_nr']['required'] = true;
return $fields;
}

function example_ajax_request( ) {

if ( isset($_REQUEST) ) {
    
    add_filter( 'woocommerce_billing_fields', 'sv_unrequire_wc_phone_field');
}  


 die();
}

add_action( 'wp_ajax_example_ajax_request', 'example_ajax_request' );
add_action('wp_ajax_nopriv_example_ajax_request', 'example_ajax_request' );

Somehow, i can't get the fields to be required.