Can you recommend new hooks?

Hello

Could you please tell me about new hooks/methods for adding custom fields to the dashboard after updating MultivendorX from 5.0 and above?

Our code worked fine before:

<?php


function art_woo_add_mark_codes() {
	global $product, $post;
	echo '<div class="options_group">';
	
	woocommerce_wp_text_input(
		[
			'id'                => '_declarax',
			'label'             => __( 'text', 'woocommerce' ),
			'placeholder'       => 'https://...',
			'desc_tip'          => 'true',
			'description'       => __( 'add site', 'woocommerce' ),
		]
	);
	
	echo '</div>';
}
add_action( 'woocommerce_product_options_general_product_data', 'art_woo_add_mark_codes' );


add_action( 'woocommerce_process_product_meta', 'art_woo_mark_codes_save', 10 );
function art_woo_mark_codes_save( $post_id ) {
	if ( isset( $_POST['_declarax'] ) ) {
		update_post_meta( $post_id, '_declarax', esc_url_raw( $_POST['_declarax'] ) );
	}
}


add_filter( 'mvx_product_data_tabs', 'add_custom_product_data_tabs_discr' );
function add_custom_product_data_tabs_discr( $tabs ) {
	$tabs['pol-opi'] = array(
		'label'    => __( 'New TAb', 'your-text-domain' ),
		'target'   => 'custom_tab_product_data_discr',
		'class'    => array(),
		'priority' => 97,
	);
	return $tabs;
}

add_action( 'mvx_product_tabs_content', 'add_custom_product_data_content_discr', 10, 3 );
function add_custom_product_data_content_discr( $pro_class_obj, $product, $post ) {
	$declarax = get_post_meta( $product->get_id(), '_declarax', true );
	?>
	<div role="tabpanel" class="tab-pane fade" id="custom_tab_product_data_discr">
		<div class="row-padding">
			<div class="form-group">
				<label class="control-label col-sm-3 col-md-3">
					<?php esc_html_e( 'text', 'woocommerce' ); ?>
				</label>
				<div class="col-md-6 col-sm-9">
					<input type="text" name="_declarax" class="form-control" value="<?php echo esc_attr( $declarax ); ?>" placeholder="https://">
				</div>
			</div>
		</div>
	</div>
	<?php
}

add_action( 'mvx_process_product_object', 'save_custom_product_data_discr', 15, 4 );
function save_custom_product_data_discr( $product, $post_data ) {
	if ( isset( $post_data['post_ID'] ) && isset( $post_data['_declarax'] ) ) {
		update_post_meta( absint( $post_data['post_ID'] ), '_declarax', esc_url_raw( $post_data['_declarax'] ) );
	}
}

However, when migrating to the new version, we encountered the problem that our old product fields are no longer visible, editable, or saveable for vendors.

Please suggest new solutions.

Thanks!