Problem on saving fields in Custom Account Tab

Hi,
I’m trying to create a custom account tab with custom fields on it, doing it this way :
1) I’ve created new fields inside an unused UM Form
2) I’ve hooked the needed actions like this :

add_filter('um_account_page_default_tabs_hook', 'test_custom_tabs_in_um', 100 );
function test_custom_tabs_in_um($tabs) {
	$tabs[00]['myteststats']        = array('icon' => 'um-icon-ios-analytics', 'title' => 'Statistics',   'custom' => true, 'show_button' => true);
	return $tabs;
}

add_action('um_account_tab__ myteststats', 'um_account_tab__ myteststats');
function um_account_tab__ myteststats( $info ) {
	global $ultimatemember;
	extract( $info );

	$output = $ultimatemember->account->get_tab_output('myteststats');
	if ( $output ) { echo $output; }
}

add_filter('um_account_content_hook_ myteststats', 'um_account_content_hook_ myteststats');
function um_account_content_hook_ myteststats( $output ){
	ob_start();
	?>
		
	<div class="um-field">
		
		<!-- Here goes your custom content -->	
<?php

    global $ultimatemember;
    $id = um_user('ID');

    $names = [ 'pilot_total_hours','pilot_hours_cdb','pilot_hours_cdb_last_year','pilot_hours_cdb_3months','pilot_hours_since_ppl'];
    
    $fields = [];
    foreach($names as $name)
       	$fields[$name] = UM()->builtin()->get_specific_field($name);
    
    $fields = apply_filters('um_account_secure_fields', $fields, get_current_user_id());

    foreach( $fields as $key => $data )
       	$output2 .= UM()->fields()->edit_field( $key, $data );

    echo str_ireplace("\\", "", $output2);
   
?>
		
	</div>
	
	<?php
		
	$output .= ob_get_contents();
	ob_end_clean();
	return $output;
}

At this point, the form is properly showing the fields, in editing mode.
But when I click on save, there’s no saving indeed. Values stays blank…
What is missing ?

Also, what is the PHP function to save values in um_user that can be retrieve by um_user(‘nameOfField’) ?

Thanks a lot